diff -r c02f464dd721 Lib/pprint.py
--- a/Lib/pprint.py	Thu Sep 26 09:35:39 2013 -0700
+++ b/Lib/pprint.py	Fri Sep 27 13:55:34 2013 +0300
@@ -37,7 +37,8 @@
 import re
 import sys as _sys
 from collections import OrderedDict as _OrderedDict
-from io import StringIO as _StringIO
+from io import StringIO as _StringIO, TextIOWrapper as _TextIOWrapper, \
+               RawIOBase as _RawIOBase
 
 __all__ = ["pprint","pformat","isreadable","isrecursive","saferepr",
            "PrettyPrinter"]
@@ -134,8 +135,27 @@
             self._stream = _sys.stdout
 
     def pprint(self, object):
-        self._format(object, self._stream, 0, 0, {}, 0)
-        self._stream.write("\n")
+        oldstream = stream = self._stream
+        encoding = getattr(stream, 'encoding', None)
+        if encoding:
+            buffer = getattr(stream, 'buffer', None)
+            if buffer is None:
+                class DecodeWriter(_RawIOBase):
+                    def writable(self):
+                        return True
+                    def write(self, data):
+                        return oldstream.write(data.decode(encoding))
+                buffer = DecodeWriter()
+            stream.flush()
+            stream = _TextIOWrapper(buffer, encoding=encoding,
+                                    errors='backslashreplace',
+                                    newline='\n', write_through=True)
+        try:
+            self._format(object, stream, 0, 0, {}, 0)
+            stream.write("\n")
+        finally:
+            if stream is not oldstream:
+                stream.detach()
 
     def pformat(self, object):
         sio = _StringIO()
diff -r c02f464dd721 Lib/test/test_pprint.py
--- a/Lib/test/test_pprint.py	Thu Sep 26 09:35:39 2013 -0700
+++ b/Lib/test/test_pprint.py	Fri Sep 27 13:55:34 2013 +0300
@@ -7,6 +7,7 @@
 import random
 import collections
 import itertools
+import io
 
 # list, tuple and dict subclasses that do or don't overwrite __repr__
 class list2(list):
@@ -513,6 +514,38 @@
             formatted = pprint.pformat(special, width=width)
             self.assertEqual(eval("(" + formatted + ")"), special)
 
+    def test_unencodable(self):
+        # with encoding and buffer
+        with io.BytesIO() as bio, \
+             io.TextIOWrapper(bio, encoding='latin1') as stream:
+            stream.write('\xab')
+            pprint.pprint('\xa3\u20ac', stream)
+            self.assertFalse(bio.closed)
+            self.assertEqual(bio.getvalue(), b"\xab'\xa3\\u20ac'\n")
+            stream.write('\xbb')
+            stream.flush()
+            self.assertFalse(bio.closed)
+            self.assertEqual(bio.getvalue(), b"\xab'\xa3\\u20ac'\n\xbb")
+        # without encoding and buffer
+        with io.StringIO() as stream:
+            stream.write('\xab')
+            pprint.pprint('\xa3\u20ac', stream)
+            self.assertEqual(stream.getvalue(), "\xab'\xa3\u20ac'\n")
+            stream.write('\xbb')
+            self.assertEqual(stream.getvalue(), "\xab'\xa3\u20ac'\n\xbb")
+        # with encoding but without buffer
+        class MockWriter(list):
+            encoding = 'latin1'
+            write = list.append
+            def flush(self):
+                pass
+        stream = MockWriter()
+        stream.write('\xab')
+        pprint.pprint('\xa3\u20ac', stream)
+        self.assertEqual(''.join(stream), "\xab'\xa3\\u20ac'\n")
+        stream.write('\xbb')
+        self.assertEqual(''.join(stream), "\xab'\xa3\\u20ac'\n\xbb")
+
 
 class DottedPrettyPrinter(pprint.PrettyPrinter):