diff --git a/ChangeLog b/ChangeLog
index a64991f541..877fb9ece4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Oct 29 00:26:00 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* win32/win32.c (rb_w32_open): need to seek to the end of the file when
+	  O_APPEND is specified.
+
 Wed Oct 29 00:08:05 2008  Tadayoshi Funaba  <tadf@dotrb.org>
 
 	* math.c (rb_math_{atan2,cos,cosh,hypot,log,sin,sinh,sqrt}): added.
diff --git a/win32/win32.c b/win32/win32.c
index 13642afa27..b70a6d7fa6 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -4129,8 +4129,10 @@ rb_w32_open(const char *file, int oflag, ...)
 	    fd = -1;
 	    goto quit;
 	}
-	if (!(flags & (FDEV | FPIPE)) && (oflag & O_APPEND))
+	if (!(flags & (FDEV | FPIPE)) && (oflag & O_APPEND)) {
 	    flags |= FAPPEND;
+	    SetFilePointer(h, 0, NULL, FILE_END);
+	}
 
 	_set_osfhnd(fd, (long)h);
 	_osfile(fd) = flags | FOPEN;