diff --git a/ChangeLog b/ChangeLog
index 36ad90498..b572f6006 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,6 @@
+20121205
+ - (tim) [defines.h] Some platforms are missing ULLONG_MAX. Feedback djm@.
+
 20121203
  - (djm) [openbsd-compat/sys-queue.h] Sync with OpenBSD to get
    TAILQ_FOREACH_SAFE needed for upcoming changes.
diff --git a/defines.h b/defines.h
index 53f83a142..54de062d3 100644
--- a/defines.h
+++ b/defines.h
@@ -25,7 +25,7 @@
 #ifndef _DEFINES_H
 #define _DEFINES_H
 
-/* $Id: defines.h,v 1.169 2012/02/15 04:13:06 tim Exp $ */
+/* $Id: defines.h,v 1.170 2012/12/04 15:50:04 tim Exp $ */
 
 
 /* Constants */
@@ -283,6 +283,10 @@ typedef unsigned char u_char;
 # define HAVE_U_CHAR
 #endif /* HAVE_U_CHAR */
 
+#ifndef ULLONG_MAX
+# define ULLONG_MAX ((unsigned long long)-1)
+#endif
+
 #ifndef SIZE_T_MAX
 #define SIZE_T_MAX ULONG_MAX
 #endif /* SIZE_T_MAX */