diff --git a/roll-dep-svn.bat b/roll-dep-svn.bat
index b2aec79..6ff5db7 100755
--- a/roll-dep-svn.bat
+++ b/roll-dep-svn.bat
@@ -1,7 +1,12 @@
-@echo off
-:: Copyright (c) 2012 The Chromium Authors. All rights reserved.
-:: Use of this source code is governed by a BSD-style license that can be
-:: found in the LICENSE file.
-
-:: Defer control.
-%~dp0python "%~dp0\roll_dep_svn.py" %*
+@echo off
+:: Copyright (c) 2012 The Chromium Authors. All rights reserved.
+:: Use of this source code is governed by a BSD-style license that can be
+:: found in the LICENSE file.
+setlocal
+
+:: Ensure that "depot_tools" is somewhere in PATH so this tool can be used
+:: standalone, but allow other PATH manipulations to take priority.
+set PATH=%PATH%;%~dp0
+
+:: Defer control.
+python "%~dp0\roll_dep_svn.py" %*