diff --git a/Python/ceval.c b/Python/ceval.c
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -2399,8 +2399,10 @@
 
         TARGET(DELETE_DEREF) {
             PyObject *cell = freevars[oparg];
-            if (PyCell_GET(cell) != NULL) {
-                PyCell_Set(cell, NULL);
+            PyObject *oldobj = PyCell_GET(cell);
+            if (oldobj != NULL) {
+                PyCell_SET(cell, NULL);
+                Py_DECREF(oldobj);
                 DISPATCH();
             }
             format_exc_unbound(co, oparg);