diff --git a/ChangeLog b/ChangeLog
index e5afb85f..5c5ef441 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2010-10-08  Daniele Varrazzo  <daniele.varrazzo@gmail.com>
+
+	* psycopg/connection_int.c: Fixed access to freed memory in
+	conn_get_isolation_level(). Bug reported by Anton Kovalev.
+
 2010-10-05  Daniele Varrazzo  <daniele.varrazzo@gmail.com>
 
 	* psycopg/cursor_type.c: Common code in execute() and mogrify() merged.
diff --git a/psycopg/connection_int.c b/psycopg/connection_int.c
index 574b6510..85d47d50 100644
--- a/psycopg/connection_int.c
+++ b/psycopg/connection_int.c
@@ -217,15 +217,19 @@ conn_get_isolation_level(PGresult *pgres)
 {
     static const char lvl1a[] = "read uncommitted";
     static const char lvl1b[] = "read committed";
-    char *isolation_level = PQgetvalue(pgres, 0, 0);
+    int rv;
 
-    CLEARPGRES(pgres);
+    char *isolation_level = PQgetvalue(pgres, 0, 0);
 
     if ((strncmp(lvl1a, isolation_level, strlen(isolation_level)) == 0)
         || (strncmp(lvl1b, isolation_level, strlen(isolation_level)) == 0))
-        return 1;
+       rv = 1;
     else /* if it's not one of the lower ones, it's SERIALIZABLE */
-        return 2;
+        rv = 2;
+
+    CLEARPGRES(pgres);
+
+    return rv;
 }
 
 int