diff --git a/Python/marshal.c b/Python/marshal.c
index 6db46e4..1cc222c 100644
--- a/Python/marshal.c
+++ b/Python/marshal.c
@@ -64,18 +64,18 @@
 	Py_ssize_t size, newsize;
 	if (p->str == NULL)
 		return; /* An error already occurred */
-	size = PyString_Size(p->str);
+	size = PyBytes_Size(p->str);
 	newsize = size + size + 1024;
 	if (newsize > 32*1024*1024) {
 		newsize = size + 1024*1024;
 	}
-	if (_PyString_Resize(&p->str, newsize) != 0) {
+	if (_PyBytes_Resize(&p->str, newsize) != 0) {
 		p->ptr = p->end = NULL;
 	}
 	else {
-		p->ptr = PyString_AS_STRING((PyStringObject *)p->str) + size;
+		p->ptr = PyBytes_AS_STRING((PyBytesObject *)p->str) + size;
 		p->end =
-			PyString_AS_STRING((PyStringObject *)p->str) + newsize;
+			PyBytes_AS_STRING((PyBytesObject *)p->str) + newsize;
 		*p->ptr++ = Py_SAFE_DOWNCAST(c, int, char);
 	}
 }
@@ -239,8 +239,8 @@
 		}
 	}
 #endif
-	else if (PyString_CheckExact(v)) {
-		if (p->strings && PyString_CHECK_INTERNED(v)) {
+	else if (PyBytes_CheckExact(v)) {
+		if (p->strings && PyBytes_CHECK_INTERNED(v)) {
 			PyObject *o = PyDict_GetItem(p->strings, v);
 			if (o) {
 				long w = PyInt_AsLong(o);
@@ -265,7 +265,7 @@
 		else {
 			w_byte(TYPE_STRING, p);
 		}
-		n = PyString_GET_SIZE(v);
+		n = PyBytes_GET_SIZE(v);
 		if (n > INT_MAX) {
 			/* huge strings are not supported */
 			p->depth--;
@@ -273,7 +273,7 @@
 			return;
 		}
 		w_long((long)n, p);
-		w_string(PyString_AS_STRING(v), (int)n, p);
+		w_string(PyBytes_AS_STRING(v), (int)n, p);
 	}
 #ifdef Py_USING_UNICODE
 	else if (PyUnicode_CheckExact(v)) {
@@ -285,14 +285,14 @@
 			return;
 		}
 		w_byte(TYPE_UNICODE, p);
-		n = PyString_GET_SIZE(utf8);
+		n = PyBytes_GET_SIZE(utf8);
 		if (n > INT_MAX) {
 			p->depth--;
 			p->error = 1;
 			return;
 		}
 		w_long((long)n, p);
-		w_string(PyString_AS_STRING(utf8), (int)n, p);
+		w_string(PyBytes_AS_STRING(utf8), (int)n, p);
 		Py_DECREF(utf8);
 	}
 #endif
@@ -713,12 +713,12 @@
 			retval = NULL;
 			break;
 		}
-		v = PyString_FromStringAndSize((char *)NULL, n);
+		v = PyBytes_FromStringAndSize((char *)NULL, n);
 		if (v == NULL) {
 			retval = NULL;
 			break;
 		}
-		if (r_string(PyString_AS_STRING(v), (int)n, p) != n) {
+		if (r_string(PyBytes_AS_STRING(v), (int)n, p) != n) {
 			Py_DECREF(v);
 			PyErr_SetString(PyExc_EOFError,
 					"EOF read where object expected");
@@ -726,7 +726,7 @@
 			break;
 		}
 		if (type == TYPE_INTERNED) {
-			PyString_InternInPlace(&v);
+			PyBytes_InternInPlace(&v);
 			if (PyList_Append(p->strings, v) < 0) {
 				retval = NULL;
 				break;
@@ -1113,11 +1113,11 @@
 {
 	WFILE wf;
 	wf.fp = NULL;
-	wf.str = PyString_FromStringAndSize((char *)NULL, 50);
+	wf.str = PyBytes_FromStringAndSize((char *)NULL, 50);
 	if (wf.str == NULL)
 		return NULL;
-	wf.ptr = PyString_AS_STRING((PyStringObject *)wf.str);
-	wf.end = wf.ptr + PyString_Size(wf.str);
+	wf.ptr = PyBytes_AS_STRING((PyBytesObject *)wf.str);
+	wf.end = wf.ptr + PyBytes_Size(wf.str);
 	wf.error = 0;
 	wf.depth = 0;
 	wf.version = version;
@@ -1125,14 +1125,14 @@
 	w_object(x, &wf);
 	Py_XDECREF(wf.strings);
 	if (wf.str != NULL) {
-		char *base = PyString_AS_STRING((PyStringObject *)wf.str);
+		char *base = PyBytes_AS_STRING((PyBytesObject *)wf.str);
 		if (wf.ptr - base > PY_SSIZE_T_MAX) {
 			Py_DECREF(wf.str);
 			PyErr_SetString(PyExc_OverflowError,
 					"too much marshall data for a string");
 			return NULL;
 		}
-		_PyString_Resize(&wf.str, (Py_ssize_t)(wf.ptr - base));
+		_PyBytes_Resize(&wf.str, (Py_ssize_t)(wf.ptr - base));
 	}
 	if (wf.error) {
 		Py_XDECREF(wf.str);