diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -401,7 +401,7 @@
 typedef struct {
     PyObject_HEAD
     PyObject *it;
-    int numread;
+    Py_ssize_t numread;
     PyObject *nextlink;
     PyObject *(values[LINKCELLS]);
 } teedataobject;
@@ -409,7 +409,7 @@
 typedef struct {
     PyObject_HEAD
     teedataobject *dataobj;
-    int index;
+    Py_ssize_t index;
     PyObject *weakreflist;
 } teeobject;
 
@@ -442,7 +442,7 @@
 }
 
 static PyObject *
-teedataobject_getitem(teedataobject *tdo, int i)
+teedataobject_getitem(teedataobject *tdo, Py_ssize_t i)
 {
     PyObject *value;
 
@@ -465,7 +465,7 @@
 static int
 teedataobject_traverse(teedataobject *tdo, visitproc visit, void * arg)
 {
-    int i;
+    Py_ssize_t i;
     Py_VISIT(tdo->it);
     for (i = 0; i < tdo->numread; i++)
         Py_VISIT(tdo->values[i]);
@@ -489,7 +489,7 @@
 static int
 teedataobject_clear(teedataobject *tdo)
 {
-    int i;
+    Py_ssize_t i;
     PyObject *tmp;
 
     Py_CLEAR(tdo->it);
@@ -512,7 +512,7 @@
 static PyObject *
 teedataobject_reduce(teedataobject *tdo)
 {
-    int i;
+    Py_ssize_t i;
     /* create a temporary list of already iterated values */
     PyObject *values = PyList_New(tdo->numread);
     if (!values)
@@ -550,8 +550,7 @@
         tdo->values[i] = PyList_GET_ITEM(values, i);
         Py_INCREF(tdo->values[i]);
     }
-    /* len <= LINKCELLS < INT_MAX */
-    tdo->numread = Py_SAFE_DOWNCAST(len, Py_ssize_t, int);
+    tdo->numread = len;
 
     if (len == LINKCELLS) {
         if (next != Py_None) {
@@ -741,8 +740,8 @@
 tee_setstate(teeobject *to, PyObject *state)
 {
     teedataobject *tdo;
-    int index;
-    if (!PyArg_ParseTuple(state, "O!i", &teedataobject_type, &tdo, &index))
+    Py_ssize_t index;
+    if (!PyArg_ParseTuple(state, "O!n", &teedataobject_type, &tdo, &index))
         return NULL;
     if (index < 0 || index > LINKCELLS) {
         PyErr_SetString(PyExc_ValueError, "Index out of range");