diff --git a/tox.ini b/tox.ini
index dfbf2070..388494b9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py26,py27
+envlist = py26,py27,pep8
 
 [testenv]
 deps = -U
@@ -8,6 +8,10 @@ deps = -U
 commands =
   python ryu/tests/run_tests.py
 
+[testenv:pep8]
+commands =
+  pep8
+
 [pep8]
-exclude = vcsversion.py,.pyc,ryu/contrib,dictconfig.py
+exclude = pbr-*,.venv,.tox,.git,doc,dist,tools,vcsversion.py,.pyc,ryu/contrib,dictconfig.py
 ignore = E113