diff --git a/setup.py b/setup.py
index 8f743d4da..b43365a98 100644
--- a/setup.py
+++ b/setup.py
@@ -42,7 +42,7 @@ install_requires = [
     'python2-pythondialog>=3.2.2rc1',  # Debian squeeze support, cf. #280
     'pytz',
     'requests',
-    'setuptools',
+    'setuptools',  # pkg_resources
     'zope.component',
     'zope.interface',
 ]