diff --git a/treelib/tree.py b/treelib/tree.py
index 62d3549..6844367 100644
--- a/treelib/tree.py
+++ b/treelib/tree.py
@@ -852,7 +852,7 @@ def to_dict(self, nid=None, key=None, sort=True, reverse=False, with_data=False)
 
             for elem in queue:
                 tree_dict[ntag]["children"].append(
-                    self.to_dict(elem.identifier, with_data=with_data, sort=sort, reverse=reverse))
+                    self.to_dict(elem.identifier, key=key, with_data=with_data, sort=sort, reverse=reverse))
             if len(tree_dict[ntag]["children"]) == 0:
                 tree_dict = self[nid].tag if not with_data else \
                     {ntag: {"data": self[nid].data}}