diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index 4c7dadb..261d9fb 100644
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -1842,7 +1842,7 @@
             tarinfo.type = DIRTYPE
 
         # Directory names should have a '/' at the end.
-        if tarinfo.isdir():
+        if tarinfo.isdir() and not tarinfo.name.endswith("/"):
             tarinfo.name += "/"
 
         self.members.append(tarinfo)
diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py
index 692d72a..b1cbcf6 100644
--- a/Lib/test/test_tarfile.py
+++ b/Lib/test/test_tarfile.py
@@ -191,6 +191,13 @@
             except:
                 pass
 
+    def test_dirtype(self):
+        for tarinfo in self.tar:
+            if tarinfo.isdir():
+                self.assert_(tarinfo.name.endswith("/"))
+                self.assert_(not tarinfo.name[:-1].endswith("/"))
+
+
 class ReadStreamTest(ReadTest):
     sep = "|"
 
diff --git a/Misc/NEWS b/Misc/NEWS
index 6475b76..58f87ea 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -4,6 +4,17 @@
 
 (editors: check NEWS.help for information about editing NEWS using ReST.)
 
+What's New in Python 2.5.2c1?
+=============================
+
+*Release date: XX-XXX-XXXX*
+
+Library
+-------
+
+- tarfile.py: Fix directory names to have only one trailing slash.
+
+
 What's New in Python 2.5.1?
 =============================