diff --git a/lib/Doctrine/ORM/Query/Lexer.php b/lib/Doctrine/ORM/Query/Lexer.php
index bf0b5f6db..d5721a735 100644
--- a/lib/Doctrine/ORM/Query/Lexer.php
+++ b/lib/Doctrine/ORM/Query/Lexer.php
@@ -129,7 +129,7 @@ class Lexer extends \Doctrine\Common\Lexer
             '[a-z_\\\][a-z0-9_\:\\\]*[a-z0-9_]{1}',
             '(?:[0-9]+(?:[\.][0-9]+)*)(?:e[+-]?[0-9]+)?',
             "'(?:[^']|'')*'",
-            '\?[0-9]*|:[a-z]{1}[a-z0-9_]{0,}'
+            '\?[0-9]*|:[a-z_][a-z0-9_]*'
         );
     }