diff --git a/actionpack/lib/action_controller/flash.rb b/actionpack/lib/action_controller/flash.rb
index 446bab5dc9..5a50d39efc 100644
--- a/actionpack/lib/action_controller/flash.rb
+++ b/actionpack/lib/action_controller/flash.rb
@@ -143,7 +143,7 @@ module ActionController #:nodoc:
       end
       
       def process_cleanup_with_flash
-        flash.sweep
+        flash.sweep if @session
         process_cleanup_without_flash
       end