diff --git a/lib/http_ntlm.c b/lib/http_ntlm.c
index 97ea0a7a46e5b8fd4dabd39419f300a0938ea41e..fd9f7009c83c68b7652b099cd4c340ef68ea0377 100644
--- a/lib/http_ntlm.c
+++ b/lib/http_ntlm.c
@@ -62,6 +62,9 @@
 #define _MPRINTF_REPLACE /* use our functions only */
 #include <curl/mprintf.h>
 
+/* The last #include file should be: */
+#include "memdebug.h"
+
 #if DEBUG_ME
 # define DEBUG_OUT(x) x
 #else