diff --git a/sqlobject/postgres/pgconnection.py b/sqlobject/postgres/pgconnection.py
index 7d9f918b..3ce5ef99 100644
--- a/sqlobject/postgres/pgconnection.py
+++ b/sqlobject/postgres/pgconnection.py
@@ -139,7 +139,7 @@ def __init__(self, dsn=None, host=None, port=None, db=None,
                 if driver == 'pygresql':
                     dsn_dict["host"] = "%s:%d" % (host, port)
                 elif driver.startswith('psycopg') and \
-                        psycopg.__version__.split('.')[0] == '1':
+                        self.module.__version__.split('.')[0] == '1':
                     dsn_dict["port"] = str(port)
                 else:
                     dsn_dict["port"] = port