diff --git a/schema/PRESUBMIT.py b/schema/PRESUBMIT.py
new file mode 100644
index 0000000..e07745c
--- /dev/null
+++ b/schema/PRESUBMIT.py
@@ -0,0 +1,35 @@
+# Copyright 2016 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 or at
+# https://developers.google.com/open-source/licenses/bsd
+
+"""Presubmit script just for Monorail's SQL files."""
+from __future__ import print_function
+from __future__ import division
+from __future__ import absolute_import
+
+
+def AlterTableCheck(input_api, output_api):  # pragma: no cover
+  this_dir = input_api.PresubmitLocalPath()
+  sql_files = set(x for x in input_api.os_listdir(this_dir)
+                  if (x.endswith('.sql') and x != 'queries.sql'))
+  log_file = input_api.os_path.join(this_dir, 'alter-table-log.txt')
+  affected_files = set(f.LocalPath() for f in input_api.AffectedTextFiles())
+
+  if (any(f in affected_files for f in sql_files) ^
+      (log_file in affected_files)):
+    return [output_api.PresubmitPromptOrNotify(
+        'It looks like you have modified the sql schema without updating\n'
+        'the alter-table-log, or vice versa. Are you sure you want to do this?')
+    ]
+  return []
+
+
+def CheckChangeOnUpload(input_api, output_api):  # pragma: no cover
+  output = AlterTableCheck(input_api, output_api)
+  return output
+
+
+def CheckChangeOnCommit(input_api, output_api):  # pragma: no cover
+  output = AlterTableCheck(input_api, output_api)
+  return output