diff --git a/changelog.d/9270.misc b/changelog.d/9270.misc
new file mode 100644
index 000000000000..314f5d4484f6
--- /dev/null
+++ b/changelog.d/9270.misc
@@ -0,0 +1 @@
+Restore PyPy compatibility by using psycopg2cffi consistently.
diff --git a/synapse/storage/engines/__init__.py b/synapse/storage/engines/__init__.py
index 035f9ea6e98b..f0c6ad356480 100644
--- a/synapse/storage/engines/__init__.py
+++ b/synapse/storage/engines/__init__.py
@@ -30,9 +30,11 @@ def create_engine(database_config) -> BaseDatabaseEngine:
     if name == "psycopg2":
         # pypy requires psycopg2cffi rather than psycopg2
         if platform.python_implementation() == "PyPy":
-            import psycopg2cffi as psycopg2  # type: ignore
-        else:
-            import psycopg2  # type: ignore
+            from psycopg2cffi import compat  # type: ignore
+
+            compat.register()
+
+        import psycopg2  # type: ignore
 
         return PostgresEngine(psycopg2, database_config)