diff -r 5dcd7ee0716a Lib/_strptime.py
--- a/Lib/_strptime.py	Fri Mar 29 04:02:14 2013 +0200
+++ b/Lib/_strptime.py	Fri Mar 29 12:40:02 2013 +0200
@@ -326,7 +326,7 @@
                     bad_directive = "%"
                 del err
                 raise ValueError("'%s' is a bad directive in format '%s'" %
-                                    (bad_directive, format))
+                                    (bad_directive, format)) from None
             # IndexError only occurs when the format string is "%"
             except IndexError:
                 raise ValueError("stray %% in format '%s'" % format)
diff -r 5dcd7ee0716a Lib/test/test_time.py
--- a/Lib/test/test_time.py	Fri Mar 29 04:02:14 2013 +0200
+++ b/Lib/test/test_time.py	Fri Mar 29 12:40:02 2013 +0200
@@ -193,6 +193,12 @@
         self.assertRaises(TypeError, time.strptime, b'2009', "%Y")
         self.assertRaises(TypeError, time.strptime, '2009', b'%Y')
 
+    def test_strptime_exception_context(self):
+        try:
+            time.strptime("", "%D")
+        except ValueError as exc:
+            self.assertEqual(exc.__suppress_context__, True)
+
     def test_asctime(self):
         time.asctime(time.gmtime(self.t))