diff --git a/modules/forum/forum.module b/modules/forum/forum.module
index 3546b4f662a6ffdd87a039e4b1cd2a68a4b27c66..8fc78fbf85ce1079ccea6f64e6c989a8a6c17f4c 100644
--- a/modules/forum/forum.module
+++ b/modules/forum/forum.module
@@ -258,7 +258,7 @@ function forum_nodeapi(&$node, $op, $teaser, $page) {
       break;
 
     case 'update':
-      if (!$node->revision && db_result(db_query('SELECT tid FROM {forum} WHERE nid=%d', $node->nid))) {
+      if (empty($node->revision) && db_result(db_query('SELECT tid FROM {forum} WHERE nid=%d', $node->nid))) {
         if (!empty($node->tid)) {
           db_query('UPDATE {forum} SET tid = %d WHERE vid = %d', $node->tid, $node->vid);
         }