diff --git a/include/config-win.h b/include/config-win.h
index 53dff5d63af..b30f50f0edb 100644
--- a/include/config-win.h
+++ b/include/config-win.h
@@ -85,6 +85,7 @@
 
 #define LONGLONG_MIN	((__int64) 0x8000000000000000)
 #define LONGLONG_MAX	((__int64) 0x7FFFFFFFFFFFFFFF)
+#define ULONGLONG_MAX	((unsigned __int64) 0xFFFFFFFFFFFFFFFF)
 #define LL(A)		((__int64) A)
 
 /* Type information */
diff --git a/include/my_global.h b/include/my_global.h
index 68c331aa414..ca74cb07868 100644
--- a/include/my_global.h
+++ b/include/my_global.h
@@ -606,6 +606,7 @@ extern double		my_atof(const char*);
 /*
   Some pre-ANSI-C99 systems like AIX 5.1 and Linux/GCC 2.95 define
   ULONGLONG_MAX, LONGLONG_MIN, LONGLONG_MAX; we use them if they're defined.
+  Also on Windows we define these constants by hand in config-win.h.
 */
 
 #if defined(HAVE_LONG_LONG) && !defined(LONGLONG_MIN)