diff --git a/lemur/certificates/service.py b/lemur/certificates/service.py
index b4b233f1..dc56876a 100644
--- a/lemur/certificates/service.py
+++ b/lemur/certificates/service.py
@@ -63,7 +63,7 @@ def get_by_serial(serial):
     :param serial:
     :return:
     """
-    return database.get(Certificate, serial, field='serial')
+    return Certificate.filter(Certificate.serial == serial).all()
 
 
 def delete(cert_id):
diff --git a/lemur/sources/service.py b/lemur/sources/service.py
index 01121374..9d140049 100644
--- a/lemur/sources/service.py
+++ b/lemur/sources/service.py
@@ -115,7 +115,7 @@ def sync_certificates(source, user):
 
     for certificate in certificates:
         if certificate.get('name'):
-            exists = certificate_service.get_by_name(certificate['name'])
+            exists = [certificate_service.get_by_name(certificate['name'])]
 
         elif certificate.get('serial'):
             exists = certificate_service.get_by_serial(certificate['serial'])
@@ -134,10 +134,11 @@ def sync_certificates(source, user):
             new += 1
 
         else:
-            if certificate.get('external_id'):
-                exists.external_id = certificate['external_id']
-            certificate_update(exists, source)
-            updated += 1
+            for e in exists:
+                if certificate.get('external_id'):
+                    exists.external_id = certificate['external_id']
+                certificate_update(e, source)
+                updated += 1
 
     assert len(certificates) == new + updated