diff --git a/lib/extras.py b/lib/extras.py
index 87c9f7ce..027c587b 100644
--- a/lib/extras.py
+++ b/lib/extras.py
@@ -112,10 +112,10 @@ class DictCursor(DictCursorBase):
         DictCursorBase.__init__(self, *args, **kwargs)
         self._prefetch = 1
 
-    def execute(self, query, vars=None, async=0):
+    def execute(self, query, vars=None):
         self.index = {}
         self._query_executed = 1
-        return _cursor.execute(self, query, vars, async)
+        return _cursor.execute(self, query, vars)
 
     def callproc(self, procname, vars=None):
         self.index = {}
@@ -201,10 +201,10 @@ class RealDictCursor(DictCursorBase):
         DictCursorBase.__init__(self, *args, **kwargs)
         self._prefetch = 0
 
-    def execute(self, query, vars=None, async=0):
+    def execute(self, query, vars=None):
         self.column_mapping = []
         self._query_executed = 1
-        return _cursor.execute(self, query, vars, async)
+        return _cursor.execute(self, query, vars)
 
     def callproc(self, procname, vars=None):
         self.column_mapping = []
@@ -282,9 +282,9 @@ class LoggingConnection(_connection):
 class LoggingCursor(_cursor):
     """A cursor that logs queries using its connection logging facilities."""
 
-    def execute(self, query, vars=None, async=0):
+    def execute(self, query, vars=None):
         try:
-            return _cursor.execute(self, query, vars, async)
+            return _cursor.execute(self, query, vars)
         finally:
             self.connection.log(self.query, self)
 
@@ -325,9 +325,9 @@ class MinTimeLoggingConnection(LoggingConnection):
 class MinTimeLoggingCursor(LoggingCursor):
     """The cursor sub-class companion to `MinTimeLoggingConnection`."""
 
-    def execute(self, query, vars=None, async=0):
+    def execute(self, query, vars=None):
         self.timestamp = time.time()
-        return LoggingCursor.execute(self, query, vars, async)
+        return LoggingCursor.execute(self, query, vars)
     
     def callproc(self, procname, vars=None):
         self.timestamp = time.time()
diff --git a/psycopg/cursor_type.c b/psycopg/cursor_type.c
index 8e264b3e..358eb232 100644
--- a/psycopg/cursor_type.c
+++ b/psycopg/cursor_type.c
@@ -305,7 +305,7 @@ static PyObject *_psyco_curs_validate_sql_basic(
 }
 
 #define psyco_curs_execute_doc \
-"execute(query, vars=None, async=0) -- Execute query with bound vars."
+"execute(query, vars=None) -- Execute query with bound vars."
 
 static int
 _psyco_curs_execute(cursorObject *self,
@@ -442,29 +442,12 @@ _psyco_curs_execute(cursorObject *self,
 static PyObject *
 psyco_curs_execute(cursorObject *self, PyObject *args, PyObject *kwargs)
 {
-    long int async;
     PyObject *vars = NULL, *operation = NULL;
 
-    static char *kwlist[] = {"query", "vars", "async", NULL};
+    static char *kwlist[] = {"query", "vars", NULL};
 
-    async = self->conn->async;
-
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O|Ol", kwlist,
-                                     &operation, &vars, &async)) {
-        return NULL;
-    }
-
-    if (async != self->conn->async) {
-        if (async == 0)
-            psyco_set_error(ProgrammingError, (PyObject*)self,
-                            "can't execute a synchronous query "
-                            "from an asynchronous cursor",
-                            NULL, NULL);
-        else
-            psyco_set_error(ProgrammingError, (PyObject*)self,
-                            "can't execute an asynchronous query "
-                            "from a synchronous cursor",
-                            NULL, NULL);
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O|O", kwlist,
+                                     &operation, &vars)) {
         return NULL;
     }
 
@@ -489,7 +472,7 @@ psyco_curs_execute(cursorObject *self, PyObject *args, PyObject *kwargs)
 
     EXC_IF_CURS_CLOSED(self);
 
-    if (_psyco_curs_execute(self, operation, vars, async)) {
+    if (_psyco_curs_execute(self, operation, vars, self->conn->async)) {
         Py_INCREF(Py_None);
         return Py_None;
     }
@@ -958,41 +941,23 @@ psyco_curs_fetchall(cursorObject *self, PyObject *args)
 /* callproc method - execute a stored procedure */
 
 #define psyco_curs_callproc_doc \
-"callproc(procname, parameters=None, async=0) -- Execute stored procedure."
+"callproc(procname, parameters=None) -- Execute stored procedure."
 
 static PyObject *
 psyco_curs_callproc(cursorObject *self, PyObject *args, PyObject *kwargs)
 {
     const char *procname = NULL;
     char *sql = NULL;
-    long int async;
     Py_ssize_t procname_len, i, nparameters = 0, sl = 0;
     PyObject *parameters = Py_None;
     PyObject *operation = NULL;
     PyObject *res = NULL;
 
-    async = self->conn->async;
-
-    if (!PyArg_ParseTuple(args, "s#|Ol",
-          &procname, &procname_len, &parameters, &async
+    if (!PyArg_ParseTuple(args, "s#|O",
+          &procname, &procname_len, &parameters
        ))
     { return NULL; }
 
-    if (async != self->conn->async) {
-        if (async == 0)
-            psyco_set_error(ProgrammingError, (PyObject*)self,
-                            "can't do a synchronous function call "
-                            "from an asynchronous cursor",
-                            NULL, NULL);
-        else
-            psyco_set_error(ProgrammingError, (PyObject*)self,
-                            "can't do an asynchronous function call "
-                            "from a synchronous cursor",
-                            NULL, NULL);
-        return NULL;
-    }
-
-
     EXC_IF_CURS_CLOSED(self);
 
     if (self->name != NULL) {
@@ -1021,7 +986,7 @@ psyco_curs_callproc(cursorObject *self, PyObject *args, PyObject *kwargs)
     operation = PyString_FromString(sql);
     PyMem_Free((void*)sql);
 
-    if (_psyco_curs_execute(self, operation, parameters, async)) {
+    if (_psyco_curs_execute(self, operation, parameters, self->conn->async)) {
         Py_INCREF(parameters);
         res = parameters;
     }