diff --git a/src/Symfony/Component/Workflow/Definition.php b/src/Symfony/Component/Workflow/Definition.php
index 5f8571b329a09..df9e78bf6e687 100644
--- a/src/Symfony/Component/Workflow/Definition.php
+++ b/src/Symfony/Component/Workflow/Definition.php
@@ -19,7 +19,7 @@
  * @author Grégoire Pineau <lyrixx@lyrixx.info>
  * @author Tobias Nyholm <tobias.nyholm@gmail.com>
  */
-final class Definition
+class Definition
 {
     private $places = array();
     private $transitions = array();