diff --git a/synapse/http/client.py b/synapse/http/client.py
index 9c7fa29369..8d6e89d6e7 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -57,6 +57,7 @@ class SimpleHttpClient(object):
         # BrowserLikePolicyForHTTPS which will do regular cert validation
         # 'like a browser'
         pool = HTTPConnectionPool(reactor)
+        pool.maxPersistentPerHost = 10
         self.agent = Agent(reactor, pool)
         self.version_string = hs.version_string
 
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index 9b6ba2d548..44f0b00333 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -104,6 +104,7 @@ class MatrixFederationHttpClient(object):
         self.signing_key = hs.config.signing_key[0]
         self.server_name = hs.hostname
         pool = HTTPConnectionPool(reactor)
+        pool.maxPersistentPerHost = 10
         self.agent = MatrixFederationHttpAgent(reactor, pool)
         self.clock = hs.get_clock()
         self.version_string = hs.version_string