diff --git a/reactos/dll/win32/mmdrv/mmdrv.rbuild b/reactos/dll/win32/mmdrv/mmdrv.rbuild
index abe64cd164e..794aacb7c0c 100644
--- a/reactos/dll/win32/mmdrv/mmdrv.rbuild
+++ b/reactos/dll/win32/mmdrv/mmdrv.rbuild
@@ -4,6 +4,7 @@
 	<define name="__USE_W32API" />
 	<define name="UNICODE" />
 	<define name="_UNICODE" />
+	<define name="NDEBUG" />
 	<library>ntdll</library>
 	<library>kernel32</library>
 	<library>user32</library>