diff --git a/NEWS b/NEWS
index 39af3a61..1c70c6da 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,8 @@
 What's new in psycopg 2.4.3
 ---------------------------
 
+  - Fixed segfault in case of transaction started with connection lost
+    (and possibly other events).
   - Lazy import of the slow uuid module, thanks to Marko Kreen.
 
 
diff --git a/psycopg/pqpath.c b/psycopg/pqpath.c
index cee5ce4c..1f0d5da9 100644
--- a/psycopg/pqpath.c
+++ b/psycopg/pqpath.c
@@ -344,11 +344,13 @@ pq_execute_command_locked(connectionObject *conn, const char *query,
     }
     if (*pgres == NULL) {
         Dprintf("pq_execute_command_locked: PQexec returned NULL");
+        PyEval_RestoreThread(*tstate);
         if (!PyErr_Occurred()) {
             const char *msg;
             msg = PQerrorMessage(conn->pgconn);
             if (msg && *msg) { *error = strdup(msg); }
         }
+        *tstate = PyEval_SaveThread();
         goto cleanup;
     }
 
@@ -635,11 +637,13 @@ pq_get_guc_locked(
 
     if (*pgres == NULL) {
         Dprintf("pq_get_guc_locked: PQexec returned NULL");
+        PyEval_RestoreThread(*tstate);
         if (!PyErr_Occurred()) {
             const char *msg;
             msg = PQerrorMessage(conn->pgconn);
             if (msg && *msg) { *error = strdup(msg); }
         }
+        *tstate = PyEval_SaveThread();
         goto cleanup;
     }
     if (PQresultStatus(*pgres) != PGRES_TUPLES_OK) {