>>> karl_uni = u'Karl Müller' >>> karl_uni u'Karl M\xfcller' >>> f = open('/tmp/karl.txt', 'w') >>> f.write(karl_uni) Traceback (most recent call last): File "", line 1, in UnicodeEncodeError: 'ascii' codec can't encode character u'\xfc' in position 6: ordinal not in range(128)