diff --git a/psycopg/cursor_type.c b/psycopg/cursor_type.c
index 1d055f61..bcbae3fc 100644
--- a/psycopg/cursor_type.c
+++ b/psycopg/cursor_type.c
@@ -525,6 +525,7 @@ psyco_curs_executemany(cursorObject *self, PyObject *args, PyObject *kwargs)
         }
     }
     Py_XDECREF(iter);
+    self->rowcount = -1;
 
     Py_INCREF(Py_None);
     return Py_None;
@@ -931,7 +932,7 @@ psyco_curs_callproc(cursorObject *self, PyObject *args, PyObject *kwargs)
     char *procname = NULL, *sql = NULL;
     long int async = 0;
     Py_ssize_t procname_len, i, nparameters = 0, sl = 0;
-    PyObject *parameters = NULL;
+    PyObject *parameters = Py_None;
     PyObject *operation = NULL;
     PyObject *res = NULL;
 
@@ -948,9 +949,9 @@ psyco_curs_callproc(cursorObject *self, PyObject *args, PyObject *kwargs)
         return NULL;
     }
 
-    if(parameters && parameters != Py_None) {
+    if(parameters != Py_None) {
         nparameters = PyObject_Length(parameters);
-    if (nparameters < 0) nparameters = 0;
+        if (nparameters < 0) nparameters = 0;
     }
 
     /* allocate some memory, build the SQL and create a PyString from it */
@@ -969,8 +970,8 @@ psyco_curs_callproc(cursorObject *self, PyObject *args, PyObject *kwargs)
     PyMem_Free((void*)sql);
 
     if (_psyco_curs_execute(self, operation, parameters, async)) {
-        Py_INCREF(Py_None);
-        res = Py_None;
+        Py_INCREF(parameters);
+        res = parameters;
     }
 
     Py_DECREF(operation);
diff --git a/psycopg/pqpath.c b/psycopg/pqpath.c
index f5c38689..8c2c8a16 100644
--- a/psycopg/pqpath.c
+++ b/psycopg/pqpath.c
@@ -844,6 +844,7 @@ int
 pq_fetch(cursorObject *curs)
 {
     int pgstatus, ex = -1;
+    const char *rowcount;
 
     /* even if we fail, we remove any information about the previous query */
     curs_reset(curs);
@@ -920,7 +921,11 @@ pq_fetch(cursorObject *curs)
 
     case PGRES_COMMAND_OK:
         Dprintf("pq_fetch: command returned OK (no tuples)");
-        curs->rowcount = atoi(PQcmdTuples(curs->pgres));
+        rowcount = PQcmdTuples(curs->pgres);
+        if (!rowcount || !rowcount[0])
+          curs->rowcount = -1;
+        else
+          curs->rowcount = atoi(rowcount);
         curs->lastoid = PQoidValue(curs->pgres);
         CLEARPGRES(curs->pgres);
         ex = 1;