diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index 40ca8bd2a..f99d3871e 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -255,7 +255,7 @@ class StateGroupWorkerStore(SQLBaseStore):
             # Turns out that postgres doesn't like doing a list of OR's and
             # is about 1000x slower, so we just issue a query for each specific
             # type seperately.
-            if types:
+            if types is not None:
                 clause_to_args = [
                     (
                         "AND type = ? AND state_key = ?",