diff --git a/go.mod b/go.mod
index 3bee65aa36..6cac17b113 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,4 @@
+// Deprecated: Use the "google.golang.org/protobuf" module instead.
 module github.com/golang/protobuf
 
 go 1.9