diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index dff1f67dcb..f748d9afb0 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -191,6 +191,7 @@ class SyncHandler(object):
         self.clock = hs.get_clock()
         self.response_cache = ResponseCache(hs, "sync")
         self.state = hs.get_state_handler()
+        self.auth = hs.get_auth()
 
         # ExpiringCache((User, Device)) -> LruCache(state_key => event_id)
         self.lazy_loaded_members_cache = ExpiringCache(
@@ -198,18 +199,23 @@ class SyncHandler(object):
             max_len=0, expiry_ms=LAZY_LOADED_MEMBERS_CACHE_MAX_AGE,
         )
 
+    @defer.inlineCallbacks
     def wait_for_sync_for_user(self, sync_config, since_token=None, timeout=0,
                                full_state=False):
         """Get the sync for a client if we have new data for it now. Otherwise
         wait for new data to arrive on the server. If the timeout expires, then
         return an empty sync result.
         Returns:
-            A Deferred SyncResult.
+            Deferred[SyncResult]
         """
-        return self.response_cache.wrap(
-            sync_config.request_key,
-            self._wait_for_sync_for_user,
-            sync_config, since_token, timeout, full_state,
+        yield self.auth.check_auth_blocking()
+
+        defer.returnValue(
+            self.response_cache.wrap(
+                sync_config.request_key,
+                self._wait_for_sync_for_user,
+                sync_config, since_token, timeout, full_state,
+            )
         )
 
     @defer.inlineCallbacks
diff --git a/tests/handlers/test_sync.py b/tests/handlers/test_sync.py
new file mode 100644
index 0000000000..3b1b4d4923
--- /dev/null
+++ b/tests/handlers/test_sync.py
@@ -0,0 +1,42 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector Ltd
+#
+# 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.
+from twisted.internet import defer
+
+import tests.unittest
+import tests.utils
+from tests.utils import setup_test_homeserver
+from synapse.handlers.sync import SyncHandler, SyncConfig
+from synapse.types import UserID
+
+
+class SyncTestCase(tests.unittest.TestCase):
+    """ Tests Sync Handler. """
+
+    @defer.inlineCallbacks
+    def setUp(self):
+        self.hs = yield setup_test_homeserver()
+        self.sync_handler = SyncHandler(self.hs)
+
+    @defer.inlineCallbacks
+    def test_wait_for_sync_for_user_auth_blocking(self):
+        sync_config = SyncConfig(
+            user=UserID("@user","server"),
+            filter_collection=None,
+            is_guest=False,
+            request_key="request_key",
+            device_id="device_id",
+        )
+        res = yield self.sync_handler.wait_for_sync_for_user(sync_config)
+        print res