diff --git a/psycopg/connection.h b/psycopg/connection.h
index 9647ffd2..01cc6a44 100644
--- a/psycopg/connection.h
+++ b/psycopg/connection.h
@@ -141,6 +141,7 @@ HIDDEN void conn_notifies_process(connectionObject *self);
 RAISES_NEG HIDDEN int  conn_setup(connectionObject *self, PGconn *pgconn);
 HIDDEN int  conn_connect(connectionObject *self, long int async);
 HIDDEN void conn_close(connectionObject *self);
+HIDDEN void conn_close_locked(connectionObject *self);
 RAISES_NEG HIDDEN int  conn_commit(connectionObject *self);
 RAISES_NEG HIDDEN int  conn_rollback(connectionObject *self);
 RAISES_NEG HIDDEN int  conn_set_session(connectionObject *self, const char *isolevel,
diff --git a/psycopg/connection_int.c b/psycopg/connection_int.c
index 8c8fed47..a93c233a 100644
--- a/psycopg/connection_int.c
+++ b/psycopg/connection_int.c
@@ -922,12 +922,24 @@ conn_close(connectionObject *self)
         return;
     }
 
-    /* sets this connection as closed even for other threads; also note that
-       we need to check the value of pgconn, because we get called even when
-       the connection fails! */
+    /* sets this connection as closed even for other threads; */
     Py_BEGIN_ALLOW_THREADS;
     pthread_mutex_lock(&self->lock);
 
+    conn_close_locked(self);
+
+    pthread_mutex_unlock(&self->lock);
+    Py_END_ALLOW_THREADS;
+}
+
+/* conn_close_locked - shut down the connection with the lock already taken */
+
+void conn_close_locked(connectionObject *self)
+{
+    if (self->closed) {
+        return;
+    }
+
     /* We used to call pq_abort_locked here, but the idea of issuing a
      * rollback on close/GC has been considered inappropriate.
      *
@@ -937,9 +949,10 @@ conn_close(connectionObject *self)
      * transaction though: to avoid these problems the transaction should be
      * closed only in status CONN_STATUS_READY.
      */
-
     self->closed = 1;
 
+    /* we need to check the value of pgconn, because we get called even when
+     * the connection fails! */
     if (self->pgconn) {
         PQfinish(self->pgconn);
         self->pgconn = NULL;
@@ -947,9 +960,6 @@ conn_close(connectionObject *self)
         PQfreeCancel(self->cancel);
         self->cancel = NULL;
     }
-
-    pthread_mutex_unlock(&self->lock);
-    Py_END_ALLOW_THREADS;
 }
 
 /* conn_commit - commit on a connection */