diff --git a/trytond/osv/osv.py b/trytond/osv/osv.py
index d9bf969cb7..d28152618d 100644
--- a/trytond/osv/osv.py
+++ b/trytond/osv/osv.py
@@ -17,7 +17,6 @@ import logging
 
 MODULE_LIST = []
 MODULE_CLASS_LIST = {}
-CLASS_POOL = {}
 
 
 class OSVService(Service):
@@ -167,7 +166,6 @@ class OSV(ORM):
         if not hasattr(cls, '_module'):
             cls._module = module
         MODULE_CLASS_LIST.setdefault(cls._module, []).append(cls)
-        CLASS_POOL[cls._name] = cls
         if module not in MODULE_LIST:
             MODULE_LIST.append(cls._module)
         return None
diff --git a/trytond/report/report.py b/trytond/report/report.py
index e80128c8cb..abd4bdc6b7 100644
--- a/trytond/report/report.py
+++ b/trytond/report/report.py
@@ -30,7 +30,6 @@ import logging
 
 MODULE_LIST = []
 MODULE_CLASS_LIST = {}
-CLASS_POOL = {}
 
 
 class ReportService(Service):
@@ -167,7 +166,6 @@ class Report(object):
         if not hasattr(cls, '_module'):
             cls._module = module
         MODULE_CLASS_LIST.setdefault(cls._module, []).append(cls)
-        CLASS_POOL[cls._name] = cls
         if module not in MODULE_LIST:
             MODULE_LIST.append(cls._module)
         return None
diff --git a/trytond/wizard/wizard.py b/trytond/wizard/wizard.py
index ca65853e00..fabffd22b2 100644
--- a/trytond/wizard/wizard.py
+++ b/trytond/wizard/wizard.py
@@ -13,7 +13,6 @@ import logging
 
 MODULE_LIST = []
 MODULE_CLASS_LIST = {}
-CLASS_POOL = {}
 
 
 class WizardService(Service):
@@ -118,7 +117,6 @@ class Wizard(object):
         if not hasattr(cls, '_module'):
             cls._module = module
         MODULE_CLASS_LIST.setdefault(cls._module, []).append(cls)
-        CLASS_POOL[cls._name] = cls
         if module not in MODULE_LIST:
             MODULE_LIST.append(cls._module)
         return None