diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index bf87d471e34a..3d93f2d032c7 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -32,6 +32,8 @@ When changes are made to authentication and project ID-related code, authenticat
 
 Known issue: If you have installed the Google Cloud SDK, be sure to log in (using `gcloud auth login`) before running tests. Though the Datastore tests use a local Datastore emulator that doesn't require authentication, they will not run if you have the Google Cloud SDK installed but aren't authenticated.
 
+**Please, do not use your production projects for executing integration tests.** While we do our best to make our tests independent of your project's state and content, they do perform create, modify and deletes, and you do not want to have your production data accidentally modified.
+
 Adding Features
 ---------------
 In order to add a feature to gcloud-java: