Index: library/Doctrine/ODM/MongoDB/Mapping/Types/TimestampType.php
===================================================================
--- library/Doctrine/ODM/MongoDB/Mapping/Types/TimestampType.php	(revision )
+++ library/Doctrine/ODM/MongoDB/Mapping/Types/TimestampType.php	(revision )
@@ -32,7 +32,7 @@
 {
     public function convertToDatabaseValue($value)
     {
-        return $value !== null ? new \MongoTimestamp($value) : null;
+        return $value !== null ? new \MongoDate($value) : null;
     }
 
     public function convertToPHPValue($value)