diff --git a/pisi/config.py b/pisi/config.py
index dc70989f..479a9595 100644
--- a/pisi/config.py
+++ b/pisi/config.py
@@ -43,6 +43,8 @@ class Options(object):
 class Config(object):
     """Config Singleton"""
 
+    __metaclass__ = pisi.util.Singleton
+
     def __init__(self, options = Options()):
         self.options = options
         self.values = pisi.configfile.ConfigurationFile("/etc/pisi/pisi.conf")
diff --git a/pisi/constants.py b/pisi/constants.py
index 04bee08a..5cf9e9ad 100644
--- a/pisi/constants.py
+++ b/pisi/constants.py
@@ -18,6 +18,8 @@ import gettext
 __trans = gettext.translation('pisi', fallback=True)
 _ = __trans.ugettext
 
+from pisi.util import Singleton
+
 class _constant:
     "Constant members implementation"
     class ConstError(TypeError):
@@ -38,6 +40,8 @@ class _constant:
 class Constants:
     "Pisi Constants Singleton"
 
+    __metaclass__ = Singleton
+
     __c = _constant()
 
     def __init__(self):