diff --git a/flask_swagger.py b/flask_swagger.py
index afee414..22c68ea 100644
--- a/flask_swagger.py
+++ b/flask_swagger.py
@@ -136,7 +136,7 @@ def spec():
                 if responses is not None:
                     defs = defs + _extract_definitions(responses.values())
                 for definition in defs:
-                    def_id = definition.get('id')
+                    def_id = definition.pop('id')
                     if def_id is not None:
                         definitions[def_id].update(definition)
                 operation = dict(