diff --git a/doc/src/extensions.rst b/doc/src/extensions.rst
index c810ae81..6df90fd2 100644
--- a/doc/src/extensions.rst
+++ b/doc/src/extensions.rst
@@ -165,9 +165,9 @@ functionalities defined by the |DBAPI|_.
         table_name
 
         A string with the error field if available; `!None` if not available.
-        The attribute value is available only if the error sent by the server
-        includes the specified field and should remain available until the
-        cursor that generated the exception executes another query.
+        The attribute value is available only if the error sent by the server:
+        not all the fields are available for all the errors and for all the
+        server versions.
 
 
 .. autofunction:: set_wait_callback(f)
diff --git a/psycopg/cursor_type.c b/psycopg/cursor_type.c
index 9570f914..a6b8c80b 100644
--- a/psycopg/cursor_type.c
+++ b/psycopg/cursor_type.c
@@ -118,7 +118,7 @@ _mogrify(PyObject *var, PyObject *fmt, cursorObject *curs, PyObject **new)
             if (kind == 2) {
                 Py_XDECREF(n);
                 psyco_set_error(ProgrammingError, curs,
-                   "argument formats can't be mixed", NULL, NULL);
+                   "argument formats can't be mixed");
                 return -1;
             }
             kind = 1;
@@ -190,7 +190,7 @@ _mogrify(PyObject *var, PyObject *fmt, cursorObject *curs, PyObject **new)
                 /* we found %( but not a ) */
                 Py_XDECREF(n);
                 psyco_set_error(ProgrammingError, curs,
-                   "incomplete placeholder: '%(' without ')'", NULL, NULL);
+                   "incomplete placeholder: '%(' without ')'");
                 return -1;
             }
             c = d + 1;  /* after the ) */
@@ -205,7 +205,7 @@ _mogrify(PyObject *var, PyObject *fmt, cursorObject *curs, PyObject **new)
             if (kind == 1) {
                 Py_XDECREF(n);
                 psyco_set_error(ProgrammingError, curs,
-                  "argument formats can't be mixed", NULL, NULL);
+                  "argument formats can't be mixed");
                 return -1;
             }
             kind = 2;
@@ -267,7 +267,7 @@ static PyObject *_psyco_curs_validate_sql_basic(
 
     if (!sql || !PyObject_IsTrue(sql)) {
         psyco_set_error(ProgrammingError, self,
-                         "can't execute an empty query", NULL, NULL);
+                         "can't execute an empty query");
         goto fail;
     }
 
@@ -338,8 +338,7 @@ _psyco_curs_merge_query_args(cursorObject *self,
                 if (!strcmp(s, "not enough arguments for format string")
                   || !strcmp(s, "not all arguments converted")) {
                     Dprintf("psyco_curs_execute:     -> got a match");
-                    psyco_set_error(ProgrammingError, self,
-                                     s, NULL, NULL);
+                    psyco_set_error(ProgrammingError, self, s);
                     pe = 1;
                 }
 
@@ -482,13 +481,12 @@ psyco_curs_execute(cursorObject *self, PyObject *args, PyObject *kwargs)
     if (self->name != NULL) {
         if (self->query != Py_None) {
             psyco_set_error(ProgrammingError, self,
-                "can't call .execute() on named cursors more than once",
-                NULL, NULL);
+                "can't call .execute() on named cursors more than once");
             return NULL;
         }
         if (self->conn->autocommit) {
             psyco_set_error(ProgrammingError, self,
-                "can't use a named cursor outside of transactions", NULL, NULL);
+                "can't use a named cursor outside of transactions");
             return NULL;
         }
         EXC_IF_NO_MARK(self);
@@ -533,7 +531,7 @@ psyco_curs_executemany(cursorObject *self, PyObject *args, PyObject *kwargs)
 
     if (self->name != NULL) {
         psyco_set_error(ProgrammingError, self,
-                "can't call .executemany() on named cursors", NULL, NULL);
+                "can't call .executemany() on named cursors");
         return NULL;
     }
 
@@ -1038,7 +1036,7 @@ psyco_curs_callproc(cursorObject *self, PyObject *args)
 
     if (self->name != NULL) {
         psyco_set_error(ProgrammingError, self,
-                         "can't call .callproc() on named cursors", NULL, NULL);
+                         "can't call .callproc() on named cursors");
         goto exit;
     }
 
@@ -1165,13 +1163,13 @@ psyco_curs_scroll(cursorObject *self, PyObject *args, PyObject *kwargs)
             newpos = value;
         } else {
             psyco_set_error(ProgrammingError, self,
-                "scroll mode must be 'relative' or 'absolute'", NULL, NULL);
+                "scroll mode must be 'relative' or 'absolute'");
             return NULL;
         }
 
         if (newpos < 0 || newpos >= self->rowcount ) {
             psyco_set_error(ProgrammingError, self,
-                             "scroll destination out of bounds", NULL, NULL);
+                             "scroll destination out of bounds");
             return NULL;
         }
 
diff --git a/psycopg/diagnostics.h b/psycopg/diagnostics.h
index adaf7580..9187c500 100644
--- a/psycopg/diagnostics.h
+++ b/psycopg/diagnostics.h
@@ -26,12 +26,14 @@
 #ifndef PSYCOPG_DIAGNOSTICS_H
 #define PSYCOPG_DIAGNOSTICS_H 1
 
+#include "psycopg/error.h"
+
 extern HIDDEN PyTypeObject diagnosticsType;
 
 typedef struct {
     PyObject_HEAD
 
-    PyObject *err;           /* exception to retrieve the diagnostics from */
+    errorObject *err;  /* exception to retrieve the diagnostics from */
 
 } diagnosticsObject;
 
diff --git a/psycopg/diagnostics_type.c b/psycopg/diagnostics_type.c
index 30ef2d46..5e302f07 100644
--- a/psycopg/diagnostics_type.c
+++ b/psycopg/diagnostics_type.c
@@ -27,7 +27,7 @@
 #include "psycopg/psycopg.h"
 
 #include "psycopg/diagnostics.h"
-#include "psycopg/cursor.h"
+#include "psycopg/error.h"
 
 /* These are new in PostgreSQL 9.3. Defining them here so that psycopg2 can
  * use them with a 9.3+ server even if compiled against pre-9.3 headers. */
@@ -55,27 +55,15 @@
 static PyObject *
 psyco_diagnostics_get_field(diagnosticsObject *self, void *closure)
 {
-    // closure contains the field code.
-    PyObject *rv = NULL;
-    PyObject *curs = NULL;
-    const char* errortext;
-    if (!(curs = PyObject_GetAttrString(self->err, "cursor")) ||
-        !PyObject_TypeCheck(curs, &cursorType) ||
-        ((cursorObject *)curs)->pgres == NULL) {
-        goto exit;
+    const char *errortext;
+
+    if (!self->err->pgres) {
+        Py_INCREF(Py_None);
+        return Py_None;
     }
-    errortext = PQresultErrorField(
-        ((cursorObject *)curs)->pgres, (Py_intptr_t) closure);
-    if (errortext) {
-        rv = conn_text_from_chars(((cursorObject *)curs)->conn, errortext);
-    }
-exit:
-    if (!rv) {
-        rv = Py_None;
-        Py_INCREF(rv);
-    }
-    Py_XDECREF(curs);
-    return rv;
+
+    errortext = PQresultErrorField(self->err->pgres, (Py_intptr_t) closure);
+    return error_text_from_chars(self->err, errortext);
 }
 
 
@@ -134,8 +122,14 @@ diagnostics_init(diagnosticsObject *self, PyObject *args, PyObject *kwds)
     if (!PyArg_ParseTuple(args, "O", &err))
         return -1;
 
+    if (!PyObject_TypeCheck(err, &errorType)) {
+        PyErr_SetString(PyExc_TypeError,
+            "The argument must be a psycopg2.Error");
+        return -1;
+    }
+
     Py_INCREF(err);
-    self->err = err;
+    self->err = (errorObject *)err;
     return 0;
 }
 
diff --git a/psycopg/error.h b/psycopg/error.h
new file mode 100644
index 00000000..9ae6dbd3
--- /dev/null
+++ b/psycopg/error.h
@@ -0,0 +1,43 @@
+/* error.h - definition for the psycopg base Error type
+ *
+ * Copyright (C) 2013  Daniele Varrazzo <daniele.varrazzo@gmail.com>
+ *
+ * This file is part of psycopg.
+ *
+ * psycopg2 is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link this program with the OpenSSL library (or with
+ * modified versions of OpenSSL that use the same license as OpenSSL),
+ * and distribute linked combinations including the two.
+ *
+ * You must obey the GNU Lesser General Public License in all respects for
+ * all of the code used other than OpenSSL.
+ *
+ * psycopg2 is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
+ * License for more details.
+ */
+
+#ifndef PSYCOPG_ERROR_H
+#define PSYCOPG_ERROR_H 1
+
+extern HIDDEN PyTypeObject errorType;
+
+typedef struct {
+    PyBaseExceptionObject exc;
+
+    PyObject *pgerror;
+    PyObject *pgcode;
+    cursorObject *cursor;
+    char *codec;
+    PGresult *pgres;
+} errorObject;
+
+HIDDEN PyObject *error_text_from_chars(errorObject *self, const char *str);
+
+#endif /* PSYCOPG_ERROR_H */
diff --git a/psycopg/error_type.c b/psycopg/error_type.c
new file mode 100644
index 00000000..cb632e0d
--- /dev/null
+++ b/psycopg/error_type.c
@@ -0,0 +1,291 @@
+/* error_type.c - python interface to the Error objects
+ *
+ * Copyright (C) 2013  Daniele Varrazzo <daniele.varrazzo@gmail.com>
+ *
+ * This file is part of psycopg.
+ *
+ * psycopg2 is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link this program with the OpenSSL library (or with
+ * modified versions of OpenSSL that use the same license as OpenSSL),
+ * and distribute linked combinations including the two.
+ *
+ * You must obey the GNU Lesser General Public License in all respects for
+ * all of the code used other than OpenSSL.
+ *
+ * psycopg2 is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
+ * License for more details.
+ */
+
+#define PSYCOPG_MODULE
+#include "psycopg/psycopg.h"
+
+#include "psycopg/error.h"
+#include "psycopg/diagnostics.h"
+#include "psycopg/pqpath.h"
+
+
+PyObject *
+error_text_from_chars(errorObject *self, const char *str)
+{
+    if (str == NULL) {
+        Py_INCREF(Py_None);
+        return (Py_None);
+    }
+
+#if PY_MAJOR_VERSION < 3
+        return PyString_FromString(str);
+#else
+        return PyUnicode_Decode(str, strlen(str),
+            self->codec ? self->codec : "ascii", "replace");
+#endif
+}
+
+
+static const char pgerror_doc[] =
+    "The error message returned by the backend, if available, else None";
+
+static const char pgcode_doc[] =
+    "The error code returned by the backend, if available, else None";
+
+static const char cursor_doc[] =
+    "The cursor that raised the exception, if available, else None";
+
+static const char diag_doc[] =
+    "A Diagnostics object to get further information about the error";
+
+static PyMemberDef error_members[] = {
+    { "pgerror", T_OBJECT, offsetof(errorObject, pgerror),
+        READONLY, (char *)pgerror_doc },
+    { "pgcode", T_OBJECT, offsetof(errorObject, pgcode),
+        READONLY, (char *)pgcode_doc },
+    { "cursor", T_OBJECT, offsetof(errorObject, cursor),
+        READONLY, (char *)cursor_doc },
+    { NULL }
+};
+
+static PyObject *
+error_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+    return ((PyTypeObject *)PyExc_StandardError)->tp_new(
+            type, args, kwargs);
+}
+
+static int
+error_init(errorObject *self, PyObject *args, PyObject *kwargs)
+{
+    if (((PyTypeObject *)PyExc_StandardError)->tp_init(
+            (PyObject *)self, args, kwargs) < 0) {
+        return -1;
+    }
+    return 0;
+}
+
+static int
+error_traverse(errorObject *self, visitproc visit, void *arg)
+{
+    Py_VISIT(self->cursor);
+    return ((PyTypeObject *)PyExc_StandardError)->tp_traverse(
+        (PyObject *)self, visit, arg);
+}
+
+static int
+error_clear(errorObject *self)
+{
+    Py_CLEAR(self->pgerror);
+    Py_CLEAR(self->pgcode);
+    Py_CLEAR(self->cursor);
+    PyMem_Free(self->codec);
+    IFCLEARPGRES(self->pgres);
+    return ((PyTypeObject *)PyExc_StandardError)->tp_clear((PyObject *)self);
+}
+
+static void
+error_dealloc(errorObject *self)
+{
+    error_clear(self);
+    return Py_TYPE(self)->tp_free((PyObject *)self);
+}
+
+
+static PyObject *
+error_get_diag(errorObject *self, void *closure)
+{
+    return PyObject_CallFunctionObjArgs(
+        (PyObject *)&diagnosticsType, (PyObject *)self, NULL);
+}
+
+static struct PyGetSetDef error_getsets[] = {
+    { "diag", (getter)error_get_diag, NULL, (char *)diag_doc },
+    { NULL }
+};
+
+
+#if PY_VERSION_HEX >= 0x02050000
+
+/* Error.__reduce__
+ *
+ * The method is required to make exceptions picklable: set the cursor
+ * attribute to None. Only working from Py 2.5: previous versions
+ * would require implementing __getstate__, and as of 2012 it's a little
+ * bit too late to care. */
+static PyObject *
+psyco_error_reduce(errorObject *self)
+{
+    PyObject *meth = NULL;
+    PyObject *tuple = NULL;
+    PyObject *dict = NULL;
+    PyObject *rv = NULL;
+
+    if (!(meth = PyObject_GetAttrString(PyExc_StandardError, "__reduce__"))) {
+        goto error;
+    }
+    if (!(tuple = PyObject_CallFunctionObjArgs(meth, self, NULL))) {
+        goto error;
+    }
+
+    /* tuple is (type, args): convert it to (type, args, dict)
+     * with our extra items in the dict.
+     *
+     * If these checks fail, we can still return a valid object. Pickle
+     * will likely fail downstream, but there's nothing else we can do here */
+    if (!PyTuple_Check(tuple)) { goto exit; }
+    if (2 != PyTuple_GET_SIZE(tuple)) { goto exit; }
+
+    if (!(dict = PyDict_New())) { goto error; }
+    if (0 != PyDict_SetItemString(dict, "pgerror", self->pgerror)) { goto error; }
+    if (0 != PyDict_SetItemString(dict, "pgcode", self->pgcode)) { goto error; }
+
+    {
+        PyObject *newtuple;
+        if (!(newtuple = PyTuple_Pack(3,
+                PyTuple_GET_ITEM(tuple, 0),
+                PyTuple_GET_ITEM(tuple, 1),
+                dict))) {
+            goto error;
+        }
+        Py_DECREF(tuple);
+        tuple = newtuple;
+    }
+
+exit:
+    rv = tuple;
+    tuple = NULL;
+
+error:
+    Py_XDECREF(dict);
+    Py_XDECREF(tuple);
+    Py_XDECREF(meth);
+
+    return rv;
+}
+
+PyObject *
+psyco_error_setstate(errorObject *self, PyObject *state)
+{
+    PyObject *rv = NULL;
+
+    /* we don't call the StandartError's setstate as it would try to load the
+     * dict content as attributes */
+
+    if (state == Py_None) {
+        goto exit;
+    }
+    if (!PyDict_Check(state)) {
+        PyErr_SetString(PyExc_TypeError, "state is not a dictionary");
+        goto error;
+    }
+
+    /* load the dict content in the structure */
+    Py_CLEAR(self->pgerror);
+    self->pgerror = PyDict_GetItemString(state, "pgerror");
+    Py_XINCREF(self->pgerror);
+
+    Py_CLEAR(self->pgcode);
+    self->pgcode = PyDict_GetItemString(state, "pgcode");
+    Py_XINCREF(self->pgcode);
+
+    Py_CLEAR(self->cursor);
+    /* We never expect a cursor in the state as it's not picklable.
+     * at most there could be a None here, coming from Psycopg < 2.5 */
+
+exit:
+    rv = Py_None;
+    Py_INCREF(rv);
+
+error:
+    return rv;
+}
+
+#endif  /* PY_VERSION_HEX >= 0x02050000 */
+
+static PyMethodDef error_methods[] = {
+#if PY_VERSION_HEX >= 0x02050000
+    /* Make Error and all its subclasses picklable.
+     *
+     * TODO: this comment applied to the __reduce_ex__ implementation: now
+     * pickling may work on Py 2.4 too... but it's 2013 now.
+     *
+     * Don't do it it on Py 2.4: [__reduce_ex__] it is not used by the pickle
+     * protocol, and if called manually fails in an unsettling way,
+     * probably because the exceptions were old-style classes. */
+    {"__reduce__", (PyCFunction)psyco_error_reduce, METH_NOARGS },
+    {"__setstate__", (PyCFunction)psyco_error_setstate, METH_O },
+#endif
+    {NULL}
+};
+
+
+PyTypeObject errorType = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    "psycopg2.Error",
+    sizeof(errorObject),
+    0,
+    (destructor)error_dealloc, /* tp_dealloc */
+    0,          /*tp_print*/
+    0,          /*tp_getattr*/
+    0,          /*tp_setattr*/
+    0,          /*tp_compare*/
+    0,          /*tp_repr*/
+    0,          /*tp_as_number*/
+    0,          /*tp_as_sequence*/
+    0,          /*tp_as_mapping*/
+    0,          /*tp_hash */
+    0,          /*tp_call*/
+    0,          /*tp_str*/
+    0,          /*tp_getattro*/
+    0,          /*tp_setattro*/
+    0,          /*tp_as_buffer*/
+    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_HAVE_GC, /*tp_flags*/
+    Error_doc, /*tp_doc*/
+    (traverseproc)error_traverse, /*tp_traverse*/
+    (inquiry)error_clear, /*tp_clear*/
+    0,          /*tp_richcompare*/
+    0,          /*tp_weaklistoffset*/
+    0,          /*tp_iter*/
+    0,          /*tp_iternext*/
+    error_methods, /*tp_methods*/
+    error_members, /*tp_members*/
+    error_getsets, /*tp_getset*/
+    0,          /*tp_base Will be set to StandardError in module init */
+    0,          /*tp_dict*/
+    0,          /*tp_descr_get*/
+    0,          /*tp_descr_set*/
+    0,          /*tp_dictoffset*/
+    (initproc)error_init, /*tp_init*/
+    0, /*tp_alloc  will be set to PyType_GenericAlloc in module init*/
+    error_new, /*tp_new*/
+    0,          /*tp_free  Low-level free-memory routine */
+    0,          /*tp_is_gc For PyObject_IS_GC */
+    0,          /*tp_bases*/
+    0,          /*tp_mro method resolution order */
+    0,          /*tp_cache*/
+    0,          /*tp_subclasses*/
+    0           /*tp_weaklist*/
+};
diff --git a/psycopg/lobject.h b/psycopg/lobject.h
index 6587198c..56f9ead4 100644
--- a/psycopg/lobject.h
+++ b/psycopg/lobject.h
@@ -78,13 +78,13 @@ RAISES_NEG HIDDEN int lobject_close(lobjectObject *self);
 #define EXC_IF_LOBJ_LEVEL0(self) \
 if (self->conn->autocommit) {                                       \
     psyco_set_error(ProgrammingError, NULL,                         \
-        "can't use a lobject outside of transactions", NULL, NULL); \
+        "can't use a lobject outside of transactions");             \
     return NULL;                                                    \
 }
 #define EXC_IF_LOBJ_UNMARKED(self) \
 if (self->conn->mark != self->mark) {                  \
     psyco_set_error(ProgrammingError, NULL,            \
-        "lobject isn't valid anymore", NULL, NULL);    \
+        "lobject isn't valid anymore");                \
     return NULL;                                       \
 }
 
diff --git a/psycopg/lobject_type.c b/psycopg/lobject_type.c
index 625a2939..fb477522 100644
--- a/psycopg/lobject_type.c
+++ b/psycopg/lobject_type.c
@@ -333,7 +333,7 @@ lobject_setup(lobjectObject *self, connectionObject *conn,
 
     if (conn->autocommit) {
         psyco_set_error(ProgrammingError, NULL,
-            "can't use a lobject outside of transactions", NULL, NULL);
+            "can't use a lobject outside of transactions");
         return -1;
     }
 
diff --git a/psycopg/microprotocols.c b/psycopg/microprotocols.c
index 23f12794..1687bc26 100644
--- a/psycopg/microprotocols.c
+++ b/psycopg/microprotocols.c
@@ -203,7 +203,7 @@ microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
     /* else set the right exception and return NULL */
     PyOS_snprintf(buffer, 255, "can't adapt type '%s'",
         Py_TYPE(obj)->tp_name);
-    psyco_set_error(ProgrammingError, NULL, buffer, NULL, NULL);
+    psyco_set_error(ProgrammingError, NULL, buffer);
     return NULL;
 }
 
diff --git a/psycopg/pqpath.c b/psycopg/pqpath.c
index 62b8c157..13f64af1 100644
--- a/psycopg/pqpath.c
+++ b/psycopg/pqpath.c
@@ -38,6 +38,7 @@
 #include "psycopg/green.h"
 #include "psycopg/typecast.h"
 #include "psycopg/pgtypes.h"
+#include "psycopg/error.h"
 
 #include <string.h>
 
@@ -149,15 +150,20 @@ exception_from_sqlstate(const char *sqlstate)
 
 /* pq_raise - raise a python exception of the right kind
 
-   This function should be called while holding the GIL. */
+   This function should be called while holding the GIL.
+
+   The function passes the ownership of the pgres to the returned exception,
+   wherer the pgres was the explicit argument or taken from the cursor.
+   So, after calling it curs->pgres will be set to null */
 
 RAISES static void
-pq_raise(connectionObject *conn, cursorObject *curs, PGresult *pgres)
+pq_raise(connectionObject *conn, cursorObject *curs, PGresult **pgres)
 {
     PyObject *exc = NULL;
     const char *err = NULL;
     const char *err2 = NULL;
     const char *code = NULL;
+    PyObject *pyerr = NULL;
 
     if (conn == NULL) {
         PyErr_SetString(DatabaseError,
@@ -171,13 +177,13 @@ pq_raise(connectionObject *conn, cursorObject *curs, PGresult *pgres)
         conn->closed = 2;
 
     if (pgres == NULL && curs != NULL)
-        pgres = curs->pgres;
+        pgres = &curs->pgres;
 
-    if (pgres) {
-        err = PQresultErrorMessage(pgres);
+    if (pgres && *pgres) {
+        err = PQresultErrorMessage(*pgres);
         if (err != NULL) {
             Dprintf("pq_raise: PQresultErrorMessage: err=%s", err);
-            code = PQresultErrorField(pgres, PG_DIAG_SQLSTATE);
+            code = PQresultErrorField(*pgres, PG_DIAG_SQLSTATE);
         }
     }
     if (err == NULL) {
@@ -210,7 +216,26 @@ pq_raise(connectionObject *conn, cursorObject *curs, PGresult *pgres)
     err2 = strip_severity(err);
     Dprintf("pq_raise: err2=%s", err2);
 
-    psyco_set_error(exc, curs, err2, err, code);
+    pyerr = psyco_set_error(exc, curs, err2);
+
+    if (pyerr && PyObject_TypeCheck(pyerr, &errorType)) {
+        errorObject *perr = (errorObject *)pyerr;
+
+        PyMem_Free(perr->codec);
+        psycopg_strdup(&perr->codec, conn->codec, 0);
+
+        Py_CLEAR(perr->pgerror);
+        perr->pgerror = error_text_from_chars(perr, err);
+
+        Py_CLEAR(perr->pgcode);
+        perr->pgcode = error_text_from_chars(perr, code);
+
+        IFCLEARPGRES(perr->pgres);
+        if (pgres && *pgres) {
+            perr->pgres = *pgres;
+            *pgres = NULL;
+        }
+    }
 }
 
 /* pq_set_critical, pq_resolve_critical - manage critical errors
@@ -388,14 +413,16 @@ pq_complete_error(connectionObject *conn, PGresult **pgres, char **error)
 {
     Dprintf("pq_complete_error: pgconn = %p, pgres = %p, error = %s",
             conn->pgconn, *pgres, *error ? *error : "(null)");
-    if (*pgres != NULL)
-        pq_raise(conn, NULL, *pgres);
+    if (*pgres != NULL) {
+        pq_raise(conn, NULL, pgres);
+        /* now *pgres is null */
+    }
     else if (*error != NULL) {
         PyErr_SetString(OperationalError, *error);
     } else {
         PyErr_SetString(OperationalError, "unknown error");
     }
-    IFCLEARPGRES(*pgres);
+
     if (*error) {
         free(*error);
         *error = NULL;
@@ -1509,8 +1536,6 @@ pq_fetch(cursorObject *curs, int no_result)
     default:
         Dprintf("pq_fetch: uh-oh, something FAILED: pgconn = %p", curs->conn);
         pq_raise(curs->conn, curs, NULL);
-        /* don't clear curs->pgres, because it contains detailed error
-           information */
         ex = -1;
         break;
     }
diff --git a/psycopg/psycopg.h b/psycopg/psycopg.h
index 2e86dca8..cc8281ed 100644
--- a/psycopg/psycopg.h
+++ b/psycopg/psycopg.h
@@ -120,8 +120,7 @@ HIDDEN PyObject *psyco_GetDecimalType(void);
 typedef struct cursorObject cursorObject;
 
 /* some utility functions */
-RAISES HIDDEN void psyco_set_error(PyObject *exc, cursorObject *curs, const char *msg,
-                            const char *pgerror, const char *pgcode);
+RAISES HIDDEN PyObject *psyco_set_error(PyObject *exc, cursorObject *curs, const char *msg);
 
 HIDDEN char *psycopg_escape_string(PyObject *conn,
               const char *from, Py_ssize_t len, char *to, Py_ssize_t *tolen);
diff --git a/psycopg/psycopgmodule.c b/psycopg/psycopgmodule.c
index 34985254..8a7539b2 100644
--- a/psycopg/psycopgmodule.c
+++ b/psycopg/psycopgmodule.c
@@ -35,6 +35,7 @@
 #include "psycopg/typecast.h"
 #include "psycopg/microprotocols.h"
 #include "psycopg/microprotocols_proto.h"
+#include "psycopg/error.h"
 #include "psycopg/diagnostics.h"
 
 #include "psycopg/adapter_qstring.h"
@@ -409,8 +410,8 @@ static struct {
     PyObject **base;
     const char *docstr;
 } exctable[] = {
-    { "psycopg2.Error", &Error, 0, Error_doc },
-    { "psycopg2.Warning", &Warning, 0, Warning_doc },
+    { "psycopg2.Error", &Error, &PyExc_StandardError, Error_doc },
+    { "psycopg2.Warning", &Warning, &PyExc_StandardError, Warning_doc },
     { "psycopg2.InterfaceError", &InterfaceError, &Error, InterfaceError_doc },
     { "psycopg2.DatabaseError", &DatabaseError, &Error, DatabaseError_doc },
     { "psycopg2.InternalError", &InternalError, &DatabaseError, InternalError_doc },
@@ -434,61 +435,6 @@ static struct {
 };
 
 
-#if PY_VERSION_HEX >= 0x02050000
-
-/* Error.__reduce_ex__
- *
- * The method is required to make exceptions picklable: set the cursor
- * attribute to None. Only working from Py 2.5: previous versions
- * would require implementing __getstate__, and as of 2012 it's a little
- * bit too late to care. */
-static PyObject *
-psyco_error_reduce_ex(PyObject *self, PyObject *args)
-{
-    PyObject *proto = NULL;
-    PyObject *super = NULL;
-    PyObject *tuple = NULL;
-    PyObject *dict = NULL;
-    PyObject *rv = NULL;
-
-    /* tuple = Exception.__reduce_ex__(self, proto) */
-    if (!PyArg_ParseTuple(args, "O", &proto)) {
-        goto error;
-    }
-    if (!(super = PyObject_GetAttrString(PyExc_Exception, "__reduce_ex__"))) {
-        goto error;
-    }
-    if (!(tuple = PyObject_CallFunctionObjArgs(super, self, proto, NULL))) {
-        goto error;
-    }
-
-    /* tuple[2]['cursor'] = None
-     *
-     * If these checks fail, we can still return a valid object. Pickle
-     * will likely fail downstream, but there's nothing else we can do here */
-    if (!PyTuple_Check(tuple)) { goto exit; }
-    if (3 > PyTuple_GET_SIZE(tuple)) { goto exit; }
-    dict = PyTuple_GET_ITEM(tuple, 2);      /* borrowed */
-    if (!PyDict_Check(dict)) { goto exit; }
-
-    /* Modify the tuple inplace and return it */
-    if (0 != PyDict_SetItemString(dict, "cursor", Py_None)) {
-        goto error;
-    }
-
-exit:
-    rv = tuple;
-    tuple = NULL;
-
-error:
-    Py_XDECREF(tuple);
-    Py_XDECREF(super);
-
-    return rv;
-}
-
-#endif  /* PY_VERSION_HEX >= 0x02050000 */
-
 static int
 psyco_errors_init(void)
 {
@@ -498,18 +444,13 @@ psyco_errors_init(void)
 
     int i;
     PyObject *dict = NULL;
-    PyObject *base;
     PyObject *str = NULL;
-    PyObject *descr = NULL;
-    PyObject *diag_property = NULL;
     int rv = -1;
 
-#if PY_VERSION_HEX >= 0x02050000
-    static PyMethodDef psyco_error_reduce_ex_def =
-        {"__reduce_ex__", psyco_error_reduce_ex, METH_VARARGS, "pickle helper"};
-#endif
+    /* 'Error' has been defined elsewhere: only init the other classes */
+    Error = (PyObject *)&errorType;
 
-    for (i=0; exctable[i].name; i++) {
+    for (i = 1; exctable[i].name; i++) {
         if (!(dict = PyDict_New())) { goto exit; }
 
         if (exctable[i].docstr) {
@@ -518,58 +459,16 @@ psyco_errors_init(void)
             Py_CLEAR(str);
         }
 
-        if (exctable[i].base == 0) {
-            #if PY_MAJOR_VERSION < 3
-            base = PyExc_StandardError;
-            #else
-            /* StandardError is gone in 3.0 */
-            base = NULL;
-            #endif
-        }
-        else
-            base = *exctable[i].base;
-
         if (!(*exctable[i].exc = PyErr_NewException(
-                exctable[i].name, base, dict))) {
+                exctable[i].name, *exctable[i].base, dict))) {
             goto exit;
         }
         Py_CLEAR(dict);
     }
 
-    /* Make pgerror, pgcode and cursor default to None on psycopg
-       error objects.  This simplifies error handling code that checks
-       these attributes. */
-    PyObject_SetAttrString(Error, "pgerror", Py_None);
-    PyObject_SetAttrString(Error, "pgcode", Py_None);
-    PyObject_SetAttrString(Error, "cursor", Py_None);
-
-    if (!(diag_property = PyObject_CallFunctionObjArgs(
-            (PyObject *) &PyProperty_Type, &diagnosticsType, NULL))) {
-        goto exit;
-    }
-    PyObject_SetAttrString(Error, "diag", diag_property);
-
-    /* install __reduce_ex__ on Error to make all the subclasses picklable.
-     *
-     * Don't install it on Py 2.4: it is not used by the pickle
-     * protocol, and if called manually fails in an unsettling way,
-     * probably because the exceptions were old-style classes. */
-#if PY_VERSION_HEX >= 0x02050000
-    if (!(descr = PyDescr_NewMethod((PyTypeObject *)Error,
-            &psyco_error_reduce_ex_def))) {
-        goto exit;
-    }
-    if (0 != PyObject_SetAttrString(Error,
-            psyco_error_reduce_ex_def.ml_name, descr)) {
-        goto exit;
-    }
-#endif
-
     rv = 0;
 
 exit:
-    Py_XDECREF(diag_property);
-    Py_XDECREF(descr);
     Py_XDECREF(str);
     Py_XDECREF(dict);
     return rv;
@@ -613,11 +512,10 @@ psyco_errors_set(PyObject *type)
 
    Create a new error of the given type with extra attributes. */
 
-RAISES void
-psyco_set_error(PyObject *exc, cursorObject *curs, const char *msg,
-                const char *pgerror, const char *pgcode)
+/* TODO: may have been changed to BORROWED */
+RAISES PyObject *
+psyco_set_error(PyObject *exc, cursorObject *curs, const char *msg)
 {
-    PyObject *t;
     PyObject *pymsg;
     PyObject *err = NULL;
     connectionObject *conn = NULL;
@@ -633,31 +531,24 @@ psyco_set_error(PyObject *exc, cursorObject *curs, const char *msg,
     else {
         /* what's better than an error in an error handler in the morning?
          * Anyway, some error was set, refcount is ok... get outta here. */
-        return;
+        return NULL;
+    }
+
+    if (err && PyObject_TypeCheck(err, &errorType)) {
+        errorObject *perr = (errorObject *)err;
+        if (curs) {
+            Py_CLEAR(perr->cursor);
+            Py_INCREF(curs);
+            perr->cursor = curs;
+        }
     }
 
     if (err) {
-        if (curs) {
-            PyObject_SetAttrString(err, "cursor", (PyObject *)curs);
-        }
-
-        if (pgerror) {
-            if ((t = conn_text_from_chars(conn, pgerror))) {
-                PyObject_SetAttrString(err, "pgerror", t);
-                Py_DECREF(t);
-            }
-        }
-
-        if (pgcode) {
-            if ((t = conn_text_from_chars(conn, pgcode))) {
-                PyObject_SetAttrString(err, "pgcode", t);
-                Py_DECREF(t);
-            }
-        }
-
         PyErr_SetObject(exc, err);
         Py_DECREF(err);
     }
+
+    return err;
 }
 
 
@@ -891,6 +782,7 @@ INIT_MODULE(_psycopg)(void)
     Py_TYPE(&chunkType)      = &PyType_Type;
     Py_TYPE(&NotifyType)     = &PyType_Type;
     Py_TYPE(&XidType)        = &PyType_Type;
+    Py_TYPE(&errorType)      = &PyType_Type;
     Py_TYPE(&diagnosticsType) = &PyType_Type;
 
     if (PyType_Ready(&connectionType) == -1) goto exit;
@@ -908,6 +800,8 @@ INIT_MODULE(_psycopg)(void)
     if (PyType_Ready(&chunkType) == -1) goto exit;
     if (PyType_Ready(&NotifyType) == -1) goto exit;
     if (PyType_Ready(&XidType) == -1) goto exit;
+    errorType.tp_base = (PyTypeObject *)PyExc_StandardError;
+    if (PyType_Ready(&errorType) == -1) goto exit;
     if (PyType_Ready(&diagnosticsType) == -1) goto exit;
 
 #ifdef PSYCOPG_EXTENSIONS
@@ -1043,6 +937,7 @@ INIT_MODULE(_psycopg)(void)
     pydatetimeType.tp_alloc = PyType_GenericAlloc;
     NotifyType.tp_alloc = PyType_GenericAlloc;
     XidType.tp_alloc = PyType_GenericAlloc;
+    errorType.tp_alloc = PyType_GenericAlloc;
     diagnosticsType.tp_alloc = PyType_GenericAlloc;
 
 #ifdef PSYCOPG_EXTENSIONS
diff --git a/psycopg/python.h b/psycopg/python.h
index f6d6be0a..9fce6e13 100644
--- a/psycopg/python.h
+++ b/psycopg/python.h
@@ -114,6 +114,7 @@ typedef unsigned long Py_uhash_t;
 #define PyInt_AsLong           PyLong_AsLong
 #define PyInt_FromLong         PyLong_FromLong
 #define PyInt_FromSsize_t      PyLong_FromSsize_t
+#define PyExc_StandardError    PyExc_Exception
 #define PyString_FromFormat    PyUnicode_FromFormat
 #define Py_TPFLAGS_HAVE_ITER   0L
 #define Py_TPFLAGS_HAVE_RICHCOMPARE 0L
diff --git a/psycopg/utils.c b/psycopg/utils.c
index 57586c57..698dcb49 100644
--- a/psycopg/utils.c
+++ b/psycopg/utils.c
@@ -115,10 +115,16 @@ psycopg_escape_identifier_easy(const char *from, Py_ssize_t len)
  *
  * Store the return in 'to' and return 0 in case of success, else return -1
  * and raise an exception.
+ *
+ * If from is null, store null into to.
  */
 RAISES_NEG int
 psycopg_strdup(char **to, const char *from, Py_ssize_t len)
 {
+    if (!from) {
+        *to = NULL;
+        return 0;
+    }
     if (!len) { len = strlen(from); }
     if (!(*to = PyMem_Malloc(len + 1))) {
         PyErr_NoMemory();
diff --git a/setup.py b/setup.py
index 41eac4ca..f747aed2 100644
--- a/setup.py
+++ b/setup.py
@@ -428,7 +428,7 @@ sources = [
 
     'connection_int.c', 'connection_type.c',
     'cursor_int.c', 'cursor_type.c',
-    'diagnostics_type.c',
+    'diagnostics_type.c', 'error_type.c',
     'lobject_int.c', 'lobject_type.c',
     'notify_type.c', 'xid_type.c',
 
@@ -441,8 +441,8 @@ sources = [
 
 depends = [
     # headers
-    'config.h', 'pgtypes.h', 'psycopg.h', 'python.h',
-    'connection.h', 'cursor.h', 'diagnostics.h', 'green.h', 'lobject.h',
+    'config.h', 'pgtypes.h', 'psycopg.h', 'python.h', 'connection.h',
+    'cursor.h', 'diagnostics.h', 'error.h', 'green.h', 'lobject.h',
     'notify.h', 'pqpath.h', 'xid.h',
 
     'adapter_asis.h', 'adapter_binary.h', 'adapter_datetime.h',
diff --git a/tests/test_module.py b/tests/test_module.py
index 1462f292..c65c019e 100755
--- a/tests/test_module.py
+++ b/tests/test_module.py
@@ -222,6 +222,38 @@ class ExceptionsTestCase(unittest.TestCase):
 
         self.assertEqual(diag.sqlstate, '42P01')
 
+    def test_diagnostics_independent(self):
+        cur = self.conn.cursor()
+        try:
+            cur.execute("l'acqua e' poca e 'a papera nun galleggia")
+        except Exception, exc:
+            diag1 = exc.diag
+
+        self.conn.rollback()
+
+        try:
+            cur.execute("select level from water where ducks > 1")
+        except psycopg2.Error, exc:
+            diag2 = exc.diag
+
+        self.assertEqual(diag1.sqlstate, '42601')
+        self.assertEqual(diag2.sqlstate, '42P01')
+
+    def test_diagnostics_from_commit(self):
+        cur = self.conn.cursor()
+        cur.execute("""
+            create temp table test_deferred (
+               data int primary key,
+               ref int references test_deferred (data)
+                   deferrable initially deferred)
+        """)
+        cur.execute("insert into test_deferred values (1,2)")
+        try:
+            self.conn.commit()
+        except psycopg2.Error, exc:
+            e = exc
+        self.assertEqual(e.diag.sqlstate, '23503')
+
     @skip_before_postgres(9, 3)
     def test_9_3_diagnostics(self):
         cur = self.conn.cursor()