diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c
index 62d934c607f..03685ce6c10 100644
--- a/Modules/mmapmodule.c
+++ b/Modules/mmapmodule.c
@@ -1391,6 +1391,7 @@ new_mmap_object(PyTypeObject *type, PyObject *args, PyObject *kwdict)
             if (size == 0) {
                 PyErr_SetString(PyExc_ValueError,
                                 "cannot mmap an empty file");
+                Py_DECREF(m_obj);
                 return NULL;
             }
             if (offset >= size) {