diff --git a/Include/pyerrors.h b/Include/pyerrors.h
index 21a4833..51d8e44 100644
--- a/Include/pyerrors.h
+++ b/Include/pyerrors.h
@@ -39,7 +39,7 @@
 
 void PyErr_SetNone Py_PROTO((PyObject *));
 void PyErr_SetObject Py_PROTO((PyObject *, PyObject *));
-void PyErr_SetString Py_PROTO((PyObject *, char *));
+void PyErr_SetString Py_PROTO((PyObject *, const char *));
 PyObject *PyErr_Occurred Py_PROTO((void));
 void PyErr_Clear Py_PROTO((void));
 void PyErr_Fetch Py_PROTO((PyObject **, PyObject **, PyObject **));
diff --git a/Include/stringobject.h b/Include/stringobject.h
index 06e572d..2c3e568 100644
--- a/Include/stringobject.h
+++ b/Include/stringobject.h
@@ -69,8 +69,8 @@
 
 #define PyString_Check(op) ((op)->ob_type == &PyString_Type)
 
-extern PyObject *PyString_FromStringAndSize Py_PROTO((char *, int));
-extern PyObject *PyString_FromString Py_PROTO((char *));
+extern PyObject *PyString_FromStringAndSize Py_PROTO((const char *, int));
+extern PyObject *PyString_FromString Py_PROTO((const char *));
 extern int PyString_Size Py_PROTO((PyObject *));
 extern char *PyString_AsString Py_PROTO((PyObject *));
 extern void PyString_Concat Py_PROTO((PyObject **, PyObject *));
diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index b880891..048b83c 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -69,7 +69,7 @@
 */
 object *
 newsizedstringobject(str, size)
-	char *str;
+	const char *str;
 	int size;
 {
 	register stringobject *op;
@@ -116,7 +116,7 @@
 
 object *
 newstringobject(str)
-	char *str;
+	const char *str;
 {
 	register unsigned int size = strlen(str);
 	register stringobject *op;
diff --git a/Python/errors.c b/Python/errors.c
index 29f3cfd..a1ab4b8 100644
--- a/Python/errors.c
+++ b/Python/errors.c
@@ -124,7 +124,7 @@
 void
 err_setstr(exception, string)
 	object *exception;
-	char *string;
+	const char *string;
 {
 	object *value = newstringobject(string);
 	err_setval(exception, value);