diff --git a/doc/administration/container_registry.md b/doc/administration/container_registry.md
index d5d433034546fe77676447cc0ceee6af1ef10605..3f4d44052d2f196448ee6e8af9d3b23b8c3eef12 100644
--- a/doc/administration/container_registry.md
+++ b/doc/administration/container_registry.md
@@ -122,6 +122,8 @@ Registry is exposed to the outside world is `4567`, here is what you need to set
 in `gitlab.rb` or `gitlab.yml` if you are using Omnibus GitLab or installed
 GitLab from source respectively.
 
+N.B. Do not choose port 5000, it will conflict with the Docker registry service.
+
 ---
 
 **Omnibus GitLab installations**