diff --git a/application/models/person/Person_model.php b/application/models/person/Person_model.php
index 94ffb78a3..8875fd4c5 100644
--- a/application/models/person/Person_model.php
+++ b/application/models/person/Person_model.php
@@ -283,8 +283,8 @@ class Person_model extends DB_Model
 								SELECT p2.person_id
 								FROM public.tbl_person p
 								JOIN public.tbl_person p2
-								ON p.vorname = p2.vorname
-								AND p.nachname = p2.nachname
+								ON lower(p.vorname) = lower(p2.vorname)
+								AND lower(p.nachname) = lower(p2.nachname)
 								AND p.gebdatum = p2.gebdatum
 								AND p.person_id = ?
 							)
@@ -310,8 +310,8 @@ class Person_model extends DB_Model
 								SELECT p2.person_id
 								FROM public.tbl_person p
 								JOIN public.tbl_person p2
-								ON p.vorname = p2.vorname
-								AND p.nachname = p2.nachname
+								ON lower(p.vorname) = lower(p2.vorname)
+								AND lower(p.nachname) = lower(p2.nachname)
 								AND p.gebdatum = p2.gebdatum
 								AND p.person_id = ?
 							)
@@ -330,7 +330,7 @@ class Person_model extends DB_Model
 					SELECT vorname, nachname, gebdatum, person_id
 					FROM tbl_person
 					) p2
-					ON (p1.vorname = p2.vorname AND p1.nachname = p2.nachname AND p1.gebdatum = p2.gebdatum)
+					ON (lower(p1.vorname) = lower(p2.vorname) AND lower(p1.nachname) = lower(p2.nachname) AND p1.gebdatum = p2.gebdatum)
 				WHERE p1.person_id != p2.person_id AND (p1.person_id = ?)";
 
 		return $this->execQuery($qry, array($person_id, $person_id, $person_id));