diff --git a/synapse/api/filtering.py b/synapse/api/filtering.py
index 922c40004..014e2e1fc 100644
--- a/synapse/api/filtering.py
+++ b/synapse/api/filtering.py
@@ -13,6 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from twisted.internet import defer
+
 
 # TODO(paul)
 _filters_for_user = {}
@@ -24,18 +26,28 @@ class Filtering(object):
         super(Filtering, self).__init__()
         self.hs = hs
 
+    @defer.inlineCallbacks
     def get_user_filter(self, user_localpart, filter_id):
         filters = _filters_for_user.get(user_localpart, None)
 
         if not filters or filter_id >= len(filters):
             raise KeyError()
 
-        return filters[filter_id]
+        # trivial yield to make it a generator so d.iC works
+        yield
+        defer.returnValue(filters[filter_id])
 
+    @defer.inlineCallbacks
     def add_user_filter(self, user_localpart, definition):
         filters = _filters_for_user.setdefault(user_localpart, [])
 
         filter_id = len(filters)
         filters.append(definition)
 
-        return filter_id
+        # trivial yield, see above
+        yield
+        defer.returnValue(filter_id)
+
+    # TODO(paul): surely we should probably add a delete_user_filter or
+    #   replace_user_filter at some point? There's no REST API specified for
+    #   them however
diff --git a/synapse/rest/client/v2_alpha/filter.py b/synapse/rest/client/v2_alpha/filter.py
index 585c8e02e..09e44e8ae 100644
--- a/synapse/rest/client/v2_alpha/filter.py
+++ b/synapse/rest/client/v2_alpha/filter.py
@@ -54,10 +54,12 @@ class GetFilterRestServlet(RestServlet):
             raise SynapseError(400, "Invalid filter_id")
 
         try:
-            defer.returnValue((200, self.filtering.get_user_filter(
+            filter = yield self.filtering.get_user_filter(
                 user_localpart=target_user.localpart,
                 filter_id=filter_id,
-            )))
+            )
+
+            defer.returnValue((200, filter))
         except KeyError:
             raise SynapseError(400, "No such filter")
 
@@ -89,7 +91,7 @@ class CreateFilterRestServlet(RestServlet):
         except:
             raise SynapseError(400, "Invalid filter definition")
 
-        filter_id = self.filtering.add_user_filter(
+        filter_id = yield self.filtering.add_user_filter(
             user_localpart=target_user.localpart,
             definition=content,
         )
diff --git a/tests/api/test_filtering.py b/tests/api/test_filtering.py
index c6c531769..fecadd105 100644
--- a/tests/api/test_filtering.py
+++ b/tests/api/test_filtering.py
@@ -53,14 +53,15 @@ class FilteringTestCase(unittest.TestCase):
 
         self.filtering = hs.get_filtering()
 
+    @defer.inlineCallbacks
     def test_filter(self):
-        filter_id = self.filtering.add_user_filter(
+        filter_id = yield self.filtering.add_user_filter(
             user_localpart=user_localpart,
             definition={"type": ["m.*"]},
         )
         self.assertEquals(filter_id, 0)
 
-        filter = self.filtering.get_user_filter(
+        filter = yield self.filtering.get_user_filter(
             user_localpart=user_localpart,
             filter_id=filter_id,
         )