diff --git a/synapse/storage/client_ips.py b/synapse/storage/client_ips.py
index 5bed255eb..f95921d73 100644
--- a/synapse/storage/client_ips.py
+++ b/synapse/storage/client_ips.py
@@ -90,9 +90,6 @@ class ClientIpStore(background_updates.BackgroundUpdateStore):
             are (user_id, device_id) tuples. The values are also dicts, with
             keys giving the column names
         """
-        if not devices:
-            defer.returnValue({})
-
         res = yield self.runInteraction(
             "get_last_client_ip_by_device",
             self._get_last_client_ip_by_device_txn,