diff --git a/.travis.yml b/.travis.yml
index fff35ca9..6281e6b4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -58,6 +58,7 @@ install:
     - python setup.py install
 script:
     - python setup.py test
+    - 2to3 . -w
     - python benchmark.py
 notifications:
   irc: "irc.freenode.org#mongoengine"