diff --git a/ChangeLog b/ChangeLog
index 46ae8cab20..135d4ec557 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Jun 17 18:11:01 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* include/ruby/win32.h (pipe): expand pipe buffer size.
+
 Tue Jun 17 17:07:35 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* win32/win32.c (CreateChild): no need to inherit handles here because
diff --git a/include/ruby/win32.h b/include/ruby/win32.h
index a340586d32..c9a03f0a23 100644
--- a/include/ruby/win32.h
+++ b/include/ruby/win32.h
@@ -134,7 +134,7 @@ extern DWORD rb_w32_osid(void);
 #define utime(_p, _t)		rb_w32_utime(_p, _t)
 #define lseek(_f, _o, _w)	_lseeki64(_f, _o, _w)
 
-#define pipe(p)			_pipe(p, 2048L, O_BINARY)
+#define pipe(p)			_pipe(p, 65536L, O_BINARY)
 #define close(h)		rb_w32_close(h)
 #define fclose(f)		rb_w32_fclose(f)
 #define read(f, b, s)		rb_w32_read(f, b, s)