diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index b403f64..03f1adb 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -1326,6 +1326,7 @@
 				PyErr_Format(PyExc_TypeError,
 			     "mro() returned a non-class ('%.500s')",
 					     cls->ob_type->tp_name);
+				Py_DECREF(tuple);
 				return -1;
 			}
 			t = (PyTypeObject*)cls;
@@ -1333,6 +1334,7 @@
 				PyErr_Format(PyExc_TypeError,
 		     "mro() returned base with unsuitable layout ('%.500s')",
 					     t->tp_name);
+				Py_DECREF(tuple);
 				return -1;
 			}
 		}