Index: django/core/servers/basehttp.py
===================================================================
--- django/core/servers/basehttp.py	(revision 6778)
+++ django/core/servers/basehttp.py	(working copy)
@@ -9,6 +9,7 @@
 
 from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
 from types import ListType, StringType
+from django.utils.safestring import SafeString
 import mimetypes
 import os
 import re
@@ -385,9 +386,9 @@
 
     def write(self, data):
         """'write()' callable as specified by PEP 333"""
+        assert type(data) in (StringType, SafeString), \
+            "write() argument must be string"
 
-        assert type(data) is StringType,"write() argument must be string"
-
         if not self.status:
             raise AssertionError("write() before start_response()")