diff --git a/hardware/arduino/sam/cores/arduino/Arduino.h b/hardware/arduino/sam/cores/arduino/Arduino.h
index c6d2aa556..ba63d6c71 100644
--- a/hardware/arduino/sam/cores/arduino/Arduino.h
+++ b/hardware/arduino/sam/cores/arduino/Arduino.h
@@ -32,6 +32,7 @@
 #include <avr/interrupt.h>
 
 #include "binary.h"
+#include "itoa.h"
 
 #ifdef __cplusplus
 extern "C"{