diff --git a/pisi/cli/commands.py b/pisi/cli/commands.py
index 03f32995..1dd192a5 100644
--- a/pisi/cli/commands.py
+++ b/pisi/cli/commands.py
@@ -493,6 +493,55 @@ to be downloaded from a repository containing sources.
                 pisi.api.build(x)
         self.finalize()
 
+class Delta(Command):
+    """Creates delta PiSi packages
+
+Usage: delta oldpackage newpackage
+
+Delta command finds the changed files between the given packages by comparing the sha1sum of the files
+and creates a delta pisi package with the changed files between two releases.
+
+"""
+    __metaclass__ = autocommand
+
+    def __init__(self, args):
+        super(Delta, self).__init__(args)
+
+    name = ("delta", "dt")
+
+    def options(self):
+
+        group = OptionGroup(self.parser, _("delta options"))
+        self.add_options(group)
+        self.parser.add_option_group(group)
+
+    def add_options(self, group):
+        group.add_option("-O", "--output-dir", action="store", default=None,
+                               help=_("Output directory for produced packages"))
+
+    def run(self):
+
+        from pisi.delta import create_delta_package 
+
+        self.init(database=False, write=False)
+
+        if len(self.args) is not 2:
+            self.help()
+            return
+
+        if ctx.get_option('output_dir'):
+            ctx.ui.info(_('Output directory: %s') % ctx.config.options.output_dir)
+        else:
+            ctx.ui.info(_('Outputting packages in the working directory.'))
+            ctx.config.options.output_dir = '.'
+
+        oldpackage = self.args[0]
+        newpackage = self.args[1]
+
+        create_delta_package(oldpackage, newpackage)
+
+        self.finalize()
+
 class Emerge(Build):
     """Build and install PiSi source packages from repository
 
diff --git a/pisi/delta.py b/pisi/delta.py
new file mode 100644
index 00000000..96112218
--- /dev/null
+++ b/pisi/delta.py
@@ -0,0 +1,90 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2007, TUBITAK/UEKAE
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation; either version 2 of the License, or (at your option)
+# any later version.
+#
+# Please read the COPYING file.
+
+import os
+from sets import Set as set
+
+import gettext
+__trans = gettext.translation('pisi', fallback=True)
+_ = __trans.ugettext
+
+import pisi.context as ctx
+from pisi.package import Package
+import pisi.util as util
+import pisi.archive as archive
+
+def create_delta_package(old_package, new_package):
+
+    oldpkg = Package(old_package, "r")
+    newpkg = Package(new_package, "r")
+
+    newmd = newpkg.get_metadata()
+    oldmd = oldpkg.get_metadata()
+
+    oldfiles = oldpkg.get_files()
+    newfiles = newpkg.get_files()
+
+    files_all = set(map(lambda x:(x.path, x.hash), newfiles.list))
+    files_old = set(map(lambda x:(x.path, x.hash), oldfiles.list))
+    files_delta = files_all - files_old
+
+    if not files_delta:
+        ctx.ui.info(_("Nothing has changed between builds, not creating a delta"))
+        return
+
+    ctx.ui.info(_("Creating delta PiSi package between %s %s") % (old_package, new_package))
+
+    # Unpack new package to temp    
+    newpkg_name = util.package_name(newmd.package.name, newmd.package.version, newmd.package.release, newmd.package.build, False)
+    newpkg_path = util.join_path(ctx.config.tmp_dir(), newpkg_name)
+    newpkg.extract_to(newpkg_path, True)
+
+    tar = archive.ArchiveTar(util.join_path(newpkg_path, ctx.const.install_tar_lzma), 'tarlzma', False, False)
+    tar.unpack_dir(newpkg_path)
+
+    # Create delta package
+    deltaname = "%s-%s-%s%s" % (oldmd.package.name, oldmd.package.release, newmd.package.release, ".delta.pisi")
+    
+    outdir = ctx.get_option('output_dir')
+    if outdir:
+        deltaname = util.join_path(outdir, deltaname)
+
+    print deltaname
+    deltapkg = Package(deltaname, "w")
+
+    c = os.getcwd()
+    os.chdir(newpkg_path)
+
+    # add comar files to package
+    for pcomar in newmd.package.providesComar:
+        fname = util.join_path(ctx.const.comar_dir, pcomar.script)
+        deltapkg.add_to_package(fname)
+
+    # add xmls and files
+    deltapkg.add_to_package(ctx.const.metadata_xml)
+    deltapkg.add_to_package(ctx.const.files_xml)
+
+    ctx.build_leftover = util.join_path(ctx.config.tmp_dir(), ctx.const.install_tar_lzma)
+
+    tar = archive.ArchiveTar(util.join_path(ctx.config.tmp_dir(), ctx.const.install_tar_lzma), "tarlzma")
+    for path, hash in files_delta:
+        tar.add_to_archive(path)
+    tar.close()
+
+    os.chdir(ctx.config.tmp_dir())
+    deltapkg.add_to_package(ctx.const.install_tar_lzma)
+    deltapkg.close()
+
+    os.unlink(util.join_path(ctx.config.tmp_dir(), ctx.const.install_tar_lzma))
+    ctx.build_leftover = None
+    os.chdir(c)
+
+    ctx.ui.info(_("Done."))
diff --git a/pisi/package.py b/pisi/package.py
index 42807766..ef309d1e 100644
--- a/pisi/package.py
+++ b/pisi/package.py
@@ -98,6 +98,11 @@ class Package:
         this is the function used by the installer"""
         self.impl.unpack_dir_flat(dir, outdir)
 
+    def extract_to(self, outdir, clean_dir = False):
+        """Extracts contents of the archive to outdir. Before extracting if clean_dir 
+        is set, outdir is deleted with its contents"""
+        self.impl.unpack(outdir, clean_dir)
+
     def extract_pisi_files(self, outdir):
         """Extract PiSi control files: metadata.xml, files.xml,
         action scripts, etc."""