diff --git a/ext/pg_connection.c b/ext/pg_connection.c
index 522fdd37e..f99739e43 100644
--- a/ext/pg_connection.c
+++ b/ext/pg_connection.c
@@ -702,7 +702,10 @@ static VALUE
 pgconn_port(VALUE self)
 {
 	char* port = PQport(pg_get_pgconn(self));
-	return INT2NUM(atoi(port));
+	if (!port || port[0] == '\0')
+		return INT2NUM(DEF_PGPORT);
+	else
+		return INT2NUM(atoi(port));
 }
 
 /*