diff --git a/src/github.com/matrix-org/dendrite/clientapi/writers/createroom.go b/src/github.com/matrix-org/dendrite/clientapi/writers/createroom.go
index 02588d328..cf78ac7d7 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/writers/createroom.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/writers/createroom.go
@@ -274,7 +274,7 @@ func eventsToMessages(events []*gomatrixserverlib.Event) ([]*sarama.ProducerMess
 			return nil, err
 		}
 		m.Topic = "clientapiOutput" // TODO: Make this customisable like roomserver is?
-		m.Key = sarama.StringEncoder("")
+		m.Key = sarama.StringEncoder(e.EventID())
 		m.Value = sarama.ByteEncoder(value)
 		msgs[i] = &m
 	}