diff --git a/tox.ini b/tox.ini
index a295abfd..4ef1c335 100644
--- a/tox.ini
+++ b/tox.ini
@@ -40,6 +40,7 @@ commands = pylint --rcfile=pylintrc taskflow
 [testenv:cover]
 basepython = python2.7
 deps = {[testenv:py27]deps}
+   coverage>=3.6
 commands = python setup.py testr --coverage --testr-args='{posargs}'
 
 [testenv:venv]