Index: Modules/_csv.c
===================================================================
--- Modules/_csv.c	(revision 70236)
+++ Modules/_csv.c	(working copy)
@@ -749,7 +749,9 @@
 Reader_iternext(ReaderObj *self)
 {
         PyObject *lineobj;
+	PyObject *unicodeobj = NULL;
         PyObject *fields = NULL;
+	char *bytestr;
         Py_UNICODE *line, c;
         Py_ssize_t linelen;
 
@@ -764,9 +766,9 @@
 					     "newline inside string");
                         return NULL;
                 }
-		if (!PyUnicode_Check(lineobj)) {
+		if (!PyUnicode_Check(lineobj) && !PyBytes_Check(lineobj)) {
 			PyErr_Format(error_obj,
-				     "iterator should return strings, "
+				     "iterator should return strings or bytes, "
 				     "not %.200s "
 				     "(did you open the file in text mode?)",
 				     lineobj->ob_type->tp_name
@@ -775,8 +777,32 @@
 			return NULL;
 		}
                 ++self->line_num;
-                line = PyUnicode_AsUnicode(lineobj);
-                linelen = PyUnicode_GetSize(lineobj);
+		if PyUnicode_Check(lineobj) {
+                	line = PyUnicode_AsUnicode(lineobj);
+                	linelen = PyUnicode_GetSize(lineobj);
+		}
+		else if PyBytes_Check(lineobj) {
+			/* the following assumes utf-8 */
+			linelen = PyBytes_Size(lineobj);
+			bytestr = PyBytes_AsString(lineobj);
+			if (bytestr == NULL) {
+				Py_DECREF(lineobj);
+				return NULL;
+			}
+			unicodeobj = PyUnicode_FromString(bytestr);
+			if (unicodeobj == NULL) {
+				Py_DECREF(lineobj);
+				return NULL;
+			}
+			line = PyUnicode_AsUnicode(unicodeobj);
+
+			/* remove old lineobj and replace with unicodeobj. */
+			Py_DECREF(lineobj);
+			lineobj = NULL;
+			lineobj = unicodeobj;
+			unicodeobj = NULL;
+		}
+
                 if (line == NULL || linelen < 0) {
                         Py_DECREF(lineobj);
                         return NULL;