diff --git a/Lib/doctest.py b/Lib/doctest.py
index b07ef6e..b6ff9fb 100644
--- a/Lib/doctest.py
+++ b/Lib/doctest.py
@@ -1173,6 +1173,8 @@ class DocTestRunner:
             out.append('Line %s, in %s' % (example.lineno+1, test.name))
         out.append('Failed example:')
         source = example.source
+        if isinstance(source, unicode):
+            source = source.encode('ASCII', 'backslashreplace')
         out.append(_indent(source))
         return '\n'.join(out)
 
diff --git a/Lib/traceback.py b/Lib/traceback.py
index 8d28afc..5d223e7 100644
--- a/Lib/traceback.py
+++ b/Lib/traceback.py
@@ -67,6 +67,8 @@ def print_tb(tb, limit=None, file=None):
                '  File "%s", line %d, in %s' % (filename, lineno, name))
         linecache.checkcache(filename)
         line = linecache.getline(filename, lineno, f.f_globals)
+        if isinstance(line, unicode):
+            line = line.encode('ASCII', 'backslashreplace')
         if line: _print(file, '    ' + line.strip())
         tb = tb.tb_next
         n = n+1