diff --git a/website/source/docs/agent/http/agent.html.markdown b/website/source/docs/agent/http/agent.html.markdown
index 33f352e6b..d23c50ab9 100644
--- a/website/source/docs/agent/http/agent.html.markdown
+++ b/website/source/docs/agent/http/agent.html.markdown
@@ -261,6 +261,8 @@ is `critical`.
 If a `TTL` type is used, then the TTL update endpoint must be used periodically to update
 the state of the check.
 
+Optionally, a `ServiceID` can be provided to associate the registered check with an existing service provided by the agent.
+
 The return code is 200 on success.
 
 ### <a name="agent_check_deregister"></a> /v1/agent/check/deregister/\<checkId\>