diff --git a/mavlink/include/mavlink/v1.0/mavlink_conversions.h b/mavlink/include/mavlink/v1.0/mavlink_conversions.h
index 1dc9088b7a..d893635770 100644
--- a/mavlink/include/mavlink/v1.0/mavlink_conversions.h
+++ b/mavlink/include/mavlink/v1.0/mavlink_conversions.h
@@ -1,6 +1,12 @@
 #ifndef  _MAVLINK_CONVERSIONS_H_
 #define  _MAVLINK_CONVERSIONS_H_
 
+/* enable math defines on Windows */
+#ifdef _MSC_VER
+#ifndef _USE_MATH_DEFINES
+#define _USE_MATH_DEFINES
+#endif
+#endif
 #include <math.h>
 
 /**