diff --git a/ChangeLog b/ChangeLog
index 0eb979374..ef4f3c398 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+20051217
+ - (dtucker) [defines.h] HP-UX system headers define "YES" and "NO" which
+   scp.c also uses, so undef them here.
+
 20051214
  - (dtucker) OpenBSD CVS Sync (regress/)
    - dtucker@cvs.openbsd.org 2005/12/30 04:36:39
@@ -3458,4 +3462,4 @@
    - (djm) Trim deprecated options from INSTALL. Mention UsePAM
    - (djm) Fix quote handling in sftp; Patch from admorten AT umich.edu
 
-$Id: ChangeLog,v 1.4028 2005/12/14 04:39:20 dtucker Exp $
+$Id: ChangeLog,v 1.4029 2005/12/17 11:04:08 dtucker Exp $
diff --git a/defines.h b/defines.h
index 92ebd2697..f25934176 100644
--- a/defines.h
+++ b/defines.h
@@ -25,7 +25,7 @@
 #ifndef _DEFINES_H
 #define _DEFINES_H
 
-/* $Id: defines.h,v 1.129 2005/10/09 01:40:04 dtucker Exp $ */
+/* $Id: defines.h,v 1.130 2005/12/17 11:04:09 dtucker Exp $ */
 
 
 /* Constants */
@@ -715,4 +715,12 @@ struct winsize {
 # undef HAVE_MMAP
 #endif
 
+/* some system headers on HP-UX define YES/NO */
+#ifdef YES
+# undef YES
+#endif
+#ifdef NO
+# undef NO
+#endif
+
 #endif /* _DEFINES_H */