diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index fee32cc3..352e57b4 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -103,9 +103,12 @@ Creating good pull requests
     sometimes what you want can be done in a different way if the reason for the
     change is known. _What goal is your change trying to accomplish?_
 
-5.  Sign the Google [Contributor License Agreement][cla] (you can sign online at
-    the bottom of that page). You _must_ sign this form, otherwise we cannot
-    merge in your changes.
+5.  **Sign the Google [Contributor License Agreement][cla]** (you can sign
+    online at the bottom of that page). You _must_ sign this form, otherwise we
+    cannot merge in your changes. **Always mention in the pull request that
+    you've signed it**, even if you signed it for a previous pull request (you
+    only need to sign the CLA once).
+
 
 [build-bots]: https://travis-ci.org/Valloric/YouCompleteMe
 [ycm-users]: https://groups.google.com/forum/?hl=en#!forum/ycm-users