--- Lib/difflib.py
+++ Lib/difflib.py
@@ -1181,11 +1181,16 @@ def unified_diff(a, b, fromfile='', tofile='', fromfiledate='',
      four
     """
 
+    if fromfiledate:
+        fromfiledate = '\t' + str(fromfiledate)
+    if tofiledate:
+        tofiledate = '\t' + str(tofiledate)
+
     started = False
     for group in SequenceMatcher(None,a,b).get_grouped_opcodes(n):
         if not started:
-            yield '--- %s %s%s' % (fromfile, fromfiledate, lineterm)
-            yield '+++ %s %s%s' % (tofile, tofiledate, lineterm)
+            yield '--- %s%s%s' % (fromfile, fromfiledate, lineterm)
+            yield '+++ %s%s%s' % (tofile, tofiledate, lineterm)
             started = True
         i1, i2, j1, j2 = group[0][1], group[-1][2], group[0][3], group[-1][4]
         yield "@@ -%d,%d +%d,%d @@%s" % (i1+1, i2-i1, j1+1, j2-j1, lineterm)
@@ -1246,12 +1251,17 @@ def context_diff(a, b, fromfile='', tofile='',
       four
     """
 
+    if fromfiledate:
+        fromfiledate = '\t' + str(fromfiledate)
+    if tofiledate:
+        tofiledate = '\t' + str(tofiledate)
+
     started = False
     prefixmap = {'insert':'+ ', 'delete':'- ', 'replace':'! ', 'equal':'  '}
     for group in SequenceMatcher(None,a,b).get_grouped_opcodes(n):
         if not started:
-            yield '*** %s %s%s' % (fromfile, fromfiledate, lineterm)
-            yield '--- %s %s%s' % (tofile, tofiledate, lineterm)
+            yield '*** %s%s%s' % (fromfile, fromfiledate, lineterm)
+            yield '--- %s%s%s' % (tofile, tofiledate, lineterm)
             started = True
 
         yield '***************%s' % (lineterm,)