diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index fad38ba..c16b60e 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -38,7 +38,7 @@ the tests against your code::
 Please use tox to test the code against supported Python and Django versions.
 First install tox::
 
-    pip install tox
+    pip install tox coverage
 
 To run tox and generate a coverage report (in ``htmlcov`` directory)::