diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py
index ca9ffdf1b..f7423f2fa 100644
--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@@ -140,7 +140,6 @@ class LruCache(object):
             list_root[NEXT] = list_root
             list_root[PREV] = list_root
             cache.clear()
-            self.size = 0
 
         @synchronized
         def cache_len():