diff --git a/COPYING.txt b/COPYING.txt
index 2a01f5cb8..4181e2d17 100644
--- a/COPYING.txt
+++ b/COPYING.txt
@@ -49,6 +49,12 @@ mapproxy/util/ext/dictspec/*.py
 (c) 2011 by Oliver Tonnhofer, Omniscale.
 MIT license.
 
+mapproxy/util/ext/itertools.py
+------------------------------
+# Copyright © 2001-2012 Python Software Foundation; All Rights Reserved
+# http://docs.python.org/library/itertools.html#itertools.izip_longest
+PSF license.
+
 mapproxy/test/schemas/*
 -----------------------
 Copyright (c) 1994 - 2010 Open Geospatial Consortium, Inc
diff --git a/mapproxy/seed/seeder.py b/mapproxy/seed/seeder.py
index 04a27f814..ba7a25bc6 100644
--- a/mapproxy/seed/seeder.py
+++ b/mapproxy/seed/seeder.py
@@ -16,12 +16,12 @@
 from __future__ import with_statement, division
 import sys
 from contextlib import contextmanager
-from itertools import izip_longest
 
 from mapproxy.config import base_config
 from mapproxy.grid import MetaGrid
 from mapproxy.source import SourceError
 from mapproxy.util import local_base_config
+from mapproxy.util.ext.itertools import izip_longest
 from mapproxy.util.lock import LockTimeout
 from mapproxy.seed.util import format_seed_task
 from mapproxy.seed.cachelock import DummyCacheLocker, CacheLockedError
diff --git a/mapproxy/util/ext/itertools.py b/mapproxy/util/ext/itertools.py
new file mode 100644
index 000000000..dfea99324
--- /dev/null
+++ b/mapproxy/util/ext/itertools.py
@@ -0,0 +1,29 @@
+# missing izip_longest function for Python 2.5 compatibility
+# http://docs.python.org/library/itertools.html#itertools.izip_longest
+# Copyright 2001-2012 Python Software Foundation; All Rights Reserved
+
+from __future__ import absolute_import
+import itertools
+
+if hasattr(itertools, 'izip_longest'):
+    izip_longest = itertools.izip_longest
+else:
+    class ZipExhausted(Exception):
+        pass
+
+    def izip_longest(*args, **kwds):
+        # izip_longest('ABCD', 'xy', fillvalue='-') --> Ax By C- D-
+        fillvalue = kwds.get('fillvalue')
+        counter = [len(args) - 1]
+        def sentinel():
+            if not counter[0]:
+                raise ZipExhausted
+            counter[0] -= 1
+            yield fillvalue
+        fillers = itertools.repeat(fillvalue)
+        iterators = [itertools.chain(it, sentinel(), fillers) for it in args]
+        try:
+            while iterators:
+                yield tuple(i.next() for i in iterators)
+        except ZipExhausted:
+            pass
\ No newline at end of file
diff --git a/mapproxy/util/ext/odict.py b/mapproxy/util/ext/odict.py
index 9a58f99dc..68c3a2421 100644
--- a/mapproxy/util/ext/odict.py
+++ b/mapproxy/util/ext/odict.py
@@ -106,6 +106,7 @@ def __setitem__(self, key, value):
     :copyright: (c) 2008 by Armin Ronacher and PEP 273 authors.
     :license: modified BSD license.
 """
+from __future__ import absolute_import
 from itertools import izip, imap
 from copy import deepcopy
 
@@ -130,7 +131,7 @@ class odict(dict):
     >>> d.update({'foo': 'bar'})
     >>> d
     odict.odict([('a', 'b'), ('c', 'd'), ('foo', 'bar')])
-    
+
     Keep in mind that when updating from dict-literals the order is not
     preserved as these dicts are unsorted!
 
@@ -179,7 +180,7 @@ class odict(dict):
     >>> d.reverse()
     >>> d
     odict.odict([('spam', []), ('foo', 'bar'), ('c', 'd'), ('a', 'b')])
-    
+
     And sort it like a list:
 
     >>> d.sort(key=lambda x: x[0].lower())