diff --git a/cpu/x86/mtarch.c b/cpu/x86/mtarch.c
index 6dd72c61f..ccc9567b8 100644
--- a/cpu/x86/mtarch.c
+++ b/cpu/x86/mtarch.c
@@ -1,5 +1,6 @@
 
 #include <stdio.h>
+#include <string.h>
 #include "sys/mt.h"
 
 #ifndef __WORDSIZE