diff --git a/api/commands.py b/api/commands.py
index 190779c..4d065c1 100644
--- a/api/commands.py
+++ b/api/commands.py
@@ -530,7 +530,7 @@ def add_owner(new_owner_name, location_name, discord_uuid=None, mc_uuid=None):
     :param discord_uuid: Discord UUID of the current owner
     :param mc_uuid: MC UUID of the current owner
     :return: Updated Location
-    :raises: PlayerNotFound, LocationLookupError
+    :raises: PlayerNotFound, LocationLookupError, PlayerInDBError
     '''
     owner = get_player(discord_uuid, mc_uuid)
 
@@ -541,6 +541,9 @@ def add_owner(new_owner_name, location_name, discord_uuid=None, mc_uuid=None):
 
     location = get_location(owner, location_name, Location)
 
+    if location.owner.filter(location__owner__name__iexact=new_owner_name):
+        raise PlayerInDBError
+
     location.owner.add(new_owner)
 
     location.save()
diff --git a/test/test_commands.py b/test/test_commands.py
index 1296af0..30e9258 100644
--- a/test/test_commands.py
+++ b/test/test_commands.py
@@ -166,3 +166,5 @@ class CommandsAPITestCase(TestCase):
         shop = Shop.objects.get(owner__name__icontains="Vakky")
 
         self.assertEquals(shop.id, self.shop.id)
+
+        self.assertRaises(PlayerInDBError, add_owner, new_owner.name, self.shop.name, discord_uuid=DISCORD_UUID)