diff --git a/cron.py b/cron.py
new file mode 100644
index 0000000..32baa05
--- /dev/null
+++ b/cron.py
@@ -0,0 +1,40 @@
+# Copyright 2014, Ian Gulliver
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import datetime
+import logging
+import webapp2
+
+from cosmopolite.lib import models
+from cosmopolite.lib import utils
+
+import config
+
+
+class CleanupPollingInstances(webapp2.RequestHandler):
+
+  @utils.local_namespace
+  def get(self):
+    cutoff = datetime.datetime.now() - datetime.timedelta(minutes=1)
+    query = (
+        models.Instance.all()
+        .filter('polling =', True)
+        .filter('last_poll <', cutoff))
+    for instance in query:
+      instance.Delete()
+
+
+app = webapp2.WSGIApplication([
+  (config.URL_PREFIX + '/cron/cleanup_polling_instances', CleanupPollingInstances),
+])