diff --git a/core/services.py b/core/services.py
index 62e86c9..3bd7aa7 100644
--- a/core/services.py
+++ b/core/services.py
@@ -35,11 +35,15 @@ class BountyService:
     def add_admin(
         self, room_id: int, admin_user_id: int, requesting_user_id: int
     ) -> None:
-        """Add an admin to a room. Requires admin permission."""
-        if not self.is_admin(room_id, requesting_user_id):
-            raise PermissionError("Only admins can add admins.")
-
+        """Add an admin to a room. Requires admin permission, or self-promotion if first admin."""
         room_data = self._storage.load(room_id)
+        has_no_admins = room_data is None or not room_data.admin_user_ids
+        is_self_promotion = requesting_user_id == admin_user_id
+
+        if not self.is_admin(room_id, requesting_user_id):
+            if not (has_no_admins and is_self_promotion):
+                raise PermissionError("Only admins can add admins.")
+
         if room_data is None:
             room_data = RoomData(
                 room_id=room_id, bounties=[], next_id=1, admin_user_ids=[]