diff --git a/Objects/iterobject.c b/Objects/iterobject.c
index 6a11772377e..c4f4e616b62 100644
--- a/Objects/iterobject.c
+++ b/Objects/iterobject.c
@@ -18,15 +18,24 @@ PySeqIter_New(PyObject *seq)
 	it->it_index = 0;
 	Py_INCREF(seq);
 	it->it_seq = seq;
+	PyObject_GC_Init(it);
 	return (PyObject *)it;
 }
 static void
 iter_dealloc(seqiterobject *it)
 {
+	PyObject_GC_Fini(it);
 	Py_DECREF(it->it_seq);
+	it = (seqiterobject *) PyObject_AS_GC(it);
 	PyObject_DEL(it);
 }
 
+static int
+iter_traverse(seqiterobject *it, visitproc visit, void *arg)
+{
+	return visit(it->it_seq, arg);
+}
+
 static PyObject *
 iter_next(seqiterobject *it, PyObject *args)
 {
@@ -97,7 +106,7 @@ PyTypeObject PySeqIter_Type = {
 	PyObject_HEAD_INIT(&PyType_Type)
 	0,					/* ob_size */
 	"iterator",				/* tp_name */
-	sizeof(seqiterobject),			/* tp_basicsize */
+	sizeof(seqiterobject) + PyGC_HEAD_SIZE,	/* tp_basicsize */
 	0,					/* tp_itemsize */
 	/* methods */
 	(destructor)iter_dealloc, 		/* tp_dealloc */
@@ -115,9 +124,9 @@ PyTypeObject PySeqIter_Type = {
 	0,					/* tp_getattro */
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
-	Py_TPFLAGS_DEFAULT,			/* tp_flags */
+	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_GC,	/* tp_flags */
  	0,					/* tp_doc */
- 	0,					/* tp_traverse */
+ 	(traverseproc)iter_traverse,		/* tp_traverse */
  	0,					/* tp_clear */
 	0,					/* tp_richcompare */
 	0,					/* tp_weaklistoffset */
@@ -144,16 +153,30 @@ PyCallIter_New(PyObject *callable, PyObject *sentinel)
 	it->it_callable = callable;
 	Py_INCREF(sentinel);
 	it->it_sentinel = sentinel;
+	PyObject_GC_Init(it);
 	return (PyObject *)it;
 }
 static void
 calliter_dealloc(calliterobject *it)
 {
+	PyObject_GC_Fini(it);
 	Py_DECREF(it->it_callable);
 	Py_DECREF(it->it_sentinel);
+	it = (calliterobject *) PyObject_AS_GC(it);
 	PyObject_DEL(it);
 }
 
+static int
+calliter_traverse(calliterobject *it, visitproc visit, void *arg)
+{
+	int err;
+	if ((err = visit(it->it_callable, arg)))
+		return err;
+	if ((err = visit(it->it_sentinel, arg)))
+		return err;
+	return 0;
+}
+
 static PyObject *
 calliter_next(calliterobject *it, PyObject *args)
 {
@@ -200,7 +223,7 @@ PyTypeObject PyCallIter_Type = {
 	PyObject_HEAD_INIT(&PyType_Type)
 	0,					/* ob_size */
 	"callable-iterator",			/* tp_name */
-	sizeof(calliterobject),			/* tp_basicsize */
+	sizeof(calliterobject) + PyGC_HEAD_SIZE,/* tp_basicsize */
 	0,					/* tp_itemsize */
 	/* methods */
 	(destructor)calliter_dealloc, 		/* tp_dealloc */
@@ -218,9 +241,9 @@ PyTypeObject PyCallIter_Type = {
 	0,					/* tp_getattro */
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
-	Py_TPFLAGS_DEFAULT,			/* tp_flags */
+	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_GC,	/* tp_flags */
  	0,					/* tp_doc */
- 	0,					/* tp_traverse */
+ 	(traverseproc)calliter_traverse,	/* tp_traverse */
  	0,					/* tp_clear */
 	0,					/* tp_richcompare */
 	0,					/* tp_weaklistoffset */