diff --git a/sys/sys/msg.h b/sys/sys/msg.h
index f759e5bd3e9..3dd70f1bc89 100644
--- a/sys/sys/msg.h
+++ b/sys/sys/msg.h
@@ -101,7 +101,6 @@ extern struct msginfo	msginfo;
 #ifndef MSGSEG
 #define MSGSEG	2048		/* must be less than 32767 */
 #endif
-#undef MSGMAX			/* ALWAYS compute MGSMAX! */
 #define MSGMAX	(MSGSSZ*MSGSEG)
 #ifndef MSGMNB
 #define MSGMNB	2048		/* max # of bytes in a queue */