diff --git a/pisi/actionsapi/shelltools.py b/pisi/actionsapi/shelltools.py
index b52368a5..1a7c3104 100644
--- a/pisi/actionsapi/shelltools.py
+++ b/pisi/actionsapi/shelltools.py
@@ -15,6 +15,7 @@ import os
 import glob
 import shutil
 import pwd
+import grp
 
 import gettext
 __trans = gettext.translation('pisi', fallback=True)
@@ -69,7 +70,7 @@ def chown(sourceFile, uid = "root", gid = "root"):
     '''change the owner and group id of sourceFile to uid and gid'''
     if can_access_file(sourceFile):
         try:
-            os.chown(sourceFile, pwd.getpwnam(uid)[2], pwd.getpwnam(gid)[3])
+            os.chown(sourceFile, pwd.getpwnam(uid)[2], grp.getgrnam(gid)[2])
         except OSError:
             ctx.ui.error(_(' ActionsAPI [chown]: Operation not permitted: %s (uid: %s, gid: %s)') \
                                                  % (sourceFile, uid, gid))