diff -r 0e56d79fa2ab Lib/_strptime.py
--- a/Lib/_strptime.py	Tue May 24 18:29:46 2011 +0200
+++ b/Lib/_strptime.py	Thu May 26 17:31:52 2011 -0500
@@ -194,6 +194,7 @@
             'd': r"(?P<d>3[0-1]|[1-2]\d|0[1-9]|[1-9]| [1-9])",
             'f': r"(?P<f>[0-9]{1,6})",
             'H': r"(?P<H>2[0-3]|[0-1]\d|\d)",
+            'G': r"(?P<G>\d\d\d\d)",
             'I': r"(?P<I>1[0-2]|0[1-9]|[1-9])",
             'j': r"(?P<j>36[0-6]|3[0-5]\d|[1-2]\d\d|0[1-9]\d|00[1-9]|[1-9]\d|0[1-9]|[1-9])",
             'm': r"(?P<m>1[0-2]|0[1-9]|[1-9])",
@@ -201,6 +202,8 @@
             'S': r"(?P<S>6[0-1]|[0-5]\d|\d)",
             'U': r"(?P<U>5[0-3]|[0-4]\d|\d)",
             'w': r"(?P<w>[0-6])",
+            'u': r"(?P<u>[1-7])",
+            'V': r"(?P<V>5[0-3]|0[1-9]|[1-4]\d|\d)",
             # W is set below by using 'U'
             'y': r"(?P<y>\d\d)",
             #XXX: Does 'Y' need to worry about having less or more than
@@ -294,6 +297,21 @@
         days_to_week = week_0_length + (7 * (week_of_year - 1))
         return 1 + days_to_week + day_of_week
 
+def _calc_julian_from_V(iso_year, iso_week, iso_weekday):
+    """Calculate the Julian day based on the ISO 8601 year, week, and weekday.
+    ISO weeks start on Mondays, with week 01 being the week containing 4 Jan.
+    ISO week days range from 1 (Monday) to 7 (Sunday).
+    """
+    correction = datetime_date(iso_year,1,4).isoweekday() + 3
+    ordinal = (iso_week * 7) + iso_weekday - correction
+    # ordinal may be negative or 0 now, which means the date is in the previous
+    # calendar year
+    if ordinal < 1:
+        ordinal += datetime_date(iso_year,1,1).toordinal()
+        ordinal -= datetime_date(iso_year-1,1,1).toordinal()
+        return iso_year - 1, ordinal
+    else:
+        return iso_year, ordinal
 
 def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
     """Return a 2-tuple consisting of a time struct and an int containing
@@ -348,6 +366,9 @@
     # though
     week_of_year = -1
     week_of_year_start = -1
+    iso_weekday = -1
+    iso_week = -1
+    iso_year = -1
     # weekday and julian defaulted to -1 so as to signal need to calculate
     # values
     weekday = julian = -1
@@ -369,6 +390,8 @@
                 year += 1900
         elif group_key == 'Y':
             year = int(found_dict['Y'])
+        elif group_key == 'G':
+            iso_year = int(found_dict['G'])
         elif group_key == 'm':
             month = int(found_dict['m'])
         elif group_key == 'B':
@@ -414,6 +437,14 @@
                 weekday = 6
             else:
                 weekday -= 1
+            iso_weekday = weekday + 1
+        elif group_key == 'u':
+            iso_weekday = int(found_dict['u'])
+            weekday = iso_weekday % 7
+            if weekday == 0:
+                weekday = 6
+            else:
+                weekday -=1
         elif group_key == 'j':
             julian = int(found_dict['j'])
         elif group_key in ('U', 'W'):
@@ -424,6 +455,8 @@
             else:
                 # W starts week on Monday.
                 week_of_year_start = 0
+        elif group_key == 'V':
+            iso_week = int(found_dict['V'])
         elif group_key == 'z':
             z = found_dict['z']
             tzoffset = int(z[1:3]) * 60 + int(z[3:5])
@@ -450,6 +483,9 @@
         week_starts_Mon = True if week_of_year_start == 0 else False
         julian = _calc_julian_from_U_or_W(year, week_of_year, weekday,
                                             week_starts_Mon)
+    elif julian == -1 and iso_week != -1 and iso_weekday != -1:
+        iso_year = year if iso_year == -1 else iso_year
+        year, julian = _calc_julian_from_V(iso_year, iso_week, iso_weekday)
     # Cannot pre-calculate datetime_date() since can change in Julian
     # calculation and thus could have different value for the day of the week
     # calculation.
diff -r 0e56d79fa2ab Lib/test/test_strptime.py
--- a/Lib/test/test_strptime.py	Tue May 24 18:29:46 2011 +0200
+++ b/Lib/test/test_strptime.py	Thu May 26 17:31:52 2011 -0500
@@ -155,8 +155,8 @@
                          "'%s' using '%s'; group 'a' = '%s', group 'b' = %s'" %
                          (found.string, found.re.pattern, found.group('a'),
                           found.group('b')))
-        for directive in ('a','A','b','B','c','d','H','I','j','m','M','p','S',
-                          'U','w','W','x','X','y','Y','Z','%'):
+        for directive in ('a','A','b','B','c','d','G','H','I','j','m','M','p',
+                          'S','u','U','V','w','W','x','X','y','Y','Z','%'):
             compiled = self.time_re.compile("%" + directive)
             found = compiled.match(time.strftime("%" + directive))
             self.assertTrue(found, "Matching failed on '%s' using '%s' regex" %
@@ -282,7 +282,7 @@
 
     def test_weekday(self):
         # Test weekday directives
-        for directive in ('A', 'a', 'w'):
+        for directive in ('A', 'a', 'w', 'u'):
             self.helper(directive,6)
 
     def test_julian(self):
@@ -443,8 +443,11 @@
         # Should be able to infer date if given year, week of year (%U or %W)
         # and day of the week
         def test_helper(ymd_tuple, test_reason):
-            for directive in ('W', 'U'):
-                format_string = "%%Y %%%s %%w" % directive
+            for directive in ('W', 'U', 'V'):
+                if directive != 'V':
+                    format_string = "%%Y %%%s %%w" % directive
+                else:
+                    format_string = "%%G %%%s %%u" % directive
                 dt_date = datetime_date(*ymd_tuple)
                 strp_input = dt_date.strftime(format_string)
                 strp_output = _strptime._strptime_time(strp_input, format_string)