diff --git a/lemur/certificates/service.py b/lemur/certificates/service.py
index dc56876a..48364652 100644
--- a/lemur/certificates/service.py
+++ b/lemur/certificates/service.py
@@ -63,7 +63,7 @@ def get_by_serial(serial):
     :param serial:
     :return:
     """
-    return Certificate.filter(Certificate.serial == serial).all()
+    return Certificate.query.filter(Certificate.serial == serial).all()
 
 
 def delete(cert_id):