diff --git a/synapse/http/client.py b/synapse/http/client.py
index 62309c336..70a19d9b7 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -40,7 +40,7 @@ from twisted.web.http import PotentialDataLoss
 from twisted.web.http_headers import Headers
 from twisted.web._newclient import ResponseDone
 
-from StringIO import StringIO
+from six import StringIO
 
 import simplejson as json
 import logging
@@ -507,7 +507,7 @@ class SpiderHttpClient(SimpleHttpClient):
                     reactor,
                     SpiderEndpointFactory(hs)
                 )
-            ), [('gzip', GzipDecoder)]
+            ), [(b'gzip', GzipDecoder)]
         )
         # We could look like Chrome:
         # self.user_agent = ("Mozilla/5.0 (%s) (KHTML, like Gecko)
diff --git a/synapse/util/logformatter.py b/synapse/util/logformatter.py
index cdbc4bffd..59ab3c696 100644
--- a/synapse/util/logformatter.py
+++ b/synapse/util/logformatter.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 
-import StringIO
+from six import StringIO
 import logging
 import traceback