diff --git a/toolkit/components/url-classifier/src/nsUrlClassifierDBService.cpp b/toolkit/components/url-classifier/src/nsUrlClassifierDBService.cpp
index 76ef4cf6742..130be76c831 100644
--- a/toolkit/components/url-classifier/src/nsUrlClassifierDBService.cpp
+++ b/toolkit/components/url-classifier/src/nsUrlClassifierDBService.cpp
@@ -556,6 +556,8 @@ nsUrlClassifierStore::Close()
   mPartialEntriesBeforeStatement = nsnull;
   mLastPartialEntriesStatement = nsnull;
 
+  mRandomStatement = nsnull;
+
   mConnection = nsnull;
 }