diff --git a/core/msg.c b/core/msg.c
index 8201153896..40846fe0f4 100644
--- a/core/msg.c
+++ b/core/msg.c
@@ -104,7 +104,7 @@ int msg_send(msg_t *m, unsigned int target_pid, bool block)
         DEBUG("msg_send: %s: Back from send block.\n", active_thread->name);
     }
     else {
-        DEBUG("msg_send: %s: Direct msg copy.\n", active_thread->name);
+        DEBUG("msg_send: %s: Direct msg copy from %i to %i.\n", active_thread->name, thread_getpid(), target_pid);
         /* copy msg to target */
         msg_t *target_message = (msg_t*) target->wait_data;
         *target_message = *m;