Index: nodequeue.module
===================================================================
--- nodequeue.module	(revision 40)
+++ nodequeue.module	(working copy)
@@ -2787,7 +2787,19 @@
     ->fields('n', array('nid', 'title'))
     ->condition('n.type', $queue->types, 'IN')
     ->range(0, 10);
+    
+  // Select nodes wich added to current nodequeue.
+  $exclude = array();
+  foreach (_nodequeue_dragdrop_get_nodes($queue, $subqueue) as $queue_node) {
+    $exclude[] = $queue_node->nid;
+  }
 
+  // Add query condition with exclude nids if nodequeue not empty.
+  if (count($exclude)) {
+    array_unique($exclude);
+    $query->condition('n.nid', $exclude, 'NOT IN');
+  }
+
   $where_args = array();
   global $user;
   if (!user_access('administer nodes', $user)) {