diff --git a/.drone.yml b/.drone.yml
index 9d7c769d8c..c4fd423e94 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -1,9 +1,9 @@
-image: python2.7
+image: python:all
 env:
   - POSTGRESQL_URI=postgresql://postgres@127.0.0.1:5432/
   - MYSQL_URI=mysql://root@127.0.0.1:3306/
 script:
   - pip install tox
-  - tox -e "py27-{sqlite,postgresql}"
+  - tox -e "{py27,py33,py34,py35}-{sqlite,postgresql}" --skip-missing-interpreters
 services:
   - postgres
diff --git a/CHANGELOG b/CHANGELOG
index ad653a417e..4b0aa46021 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,5 @@
+* Add Python3 support
+
 Version 3.8.0 - 2015-11-02
 * Bug fixes (see mercurial logs for details)
 * Remove header_A4.odt style
diff --git a/company.py b/company.py
index 4fb2278697..5e8c593170 100644
--- a/company.py
+++ b/company.py
@@ -21,7 +21,6 @@ CursorInterface.cache_keys.update({'company', 'employee'})
 __all__ = ['Company', 'Employee', 'UserEmployee', 'User', 'Property',
     'Sequence', 'SequenceStrict', 'Date', 'CompanyConfigStart',
     'CompanyConfig', 'CompanyReport', 'LetterReport', 'Rule']
-__metaclass__ = PoolMeta
 
 
 class Company(ModelSQL, ModelView):
@@ -82,6 +81,7 @@ class UserEmployee(ModelSQL):
 
 
 class User:
+    __metaclass__ = PoolMeta
     __name__ = 'res.user'
     main_company = fields.Many2One('company.company', 'Main Company')
     company = fields.Many2One('company.company', 'Current Company',
@@ -259,6 +259,7 @@ class User:
 
 
 class Property:
+    __metaclass__ = PoolMeta
     __name__ = 'ir.property'
     company = fields.Many2One('company.company', 'Company',
         domain=[
@@ -288,6 +289,7 @@ class Property:
 
 
 class Sequence:
+    __metaclass__ = PoolMeta
     __name__ = 'ir.sequence'
     company = fields.Many2One('company.company', 'Company',
         domain=[
@@ -310,6 +312,7 @@ class SequenceStrict(Sequence):
 
 
 class Date:
+    __metaclass__ = PoolMeta
     __name__ = 'ir.date'
 
     @classmethod
@@ -372,6 +375,7 @@ class LetterReport(CompanyReport):
 
 
 class Rule:
+    __metaclass__ = PoolMeta
     __name__ = 'ir.rule'
 
     @classmethod
diff --git a/cron.py b/cron.py
index f4756bf4ec..27b4243cdf 100644
--- a/cron.py
+++ b/cron.py
@@ -6,10 +6,10 @@ from trytond.transaction import Transaction
 
 
 __all__ = ['Cron', 'CronCompany']
-__metaclass__ = PoolMeta
 
 
 class Cron:
+    __metaclass__ = PoolMeta
     __name__ = "ir.cron"
     companies = fields.Many2Many('ir.cron-company.company', 'cron', 'company',
             'Companies', help='Companies registered for this cron')
diff --git a/party.py b/party.py
index f6b20df0f1..3b90805d42 100644
--- a/party.py
+++ b/party.py
@@ -4,10 +4,10 @@ from trytond.pyson import Eval
 from trytond.pool import PoolMeta
 
 __all__ = ['PartyConfiguration']
-__metaclass__ = PoolMeta
 
 
 class PartyConfiguration:
+    __metaclass__ = PoolMeta
     __name__ = 'party.configuration'
 
     @classmethod
diff --git a/setup.py b/setup.py
index 7b5d7cff77..939c05417a 100644
--- a/setup.py
+++ b/setup.py
@@ -5,11 +5,17 @@
 from setuptools import setup
 import re
 import os
-import ConfigParser
+import io
+try:
+    from configparser import ConfigParser
+except ImportError:
+    from ConfigParser import ConfigParser
 
 
 def read(fname):
-    return open(os.path.join(os.path.dirname(__file__), fname)).read()
+    return io.open(
+        os.path.join(os.path.dirname(__file__), fname),
+        'r', encoding='utf-8').read()
 
 
 def get_require_version(name):
@@ -21,7 +27,7 @@ def get_require_version(name):
         major_version, minor_version + 1)
     return require
 
-config = ConfigParser.ConfigParser()
+config = ConfigParser()
 config.readfp(open('tryton.cfg'))
 info = dict(config.items('tryton'))
 for key in ('depends', 'extras_depend', 'xml'):
@@ -89,6 +95,9 @@ setup(name=name,
         'Natural Language :: Spanish',
         'Operating System :: OS Independent',
         'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3.3',
+        'Programming Language :: Python :: 3.4',
+        'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: Implementation :: CPython',
         'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Office/Business',
@@ -105,4 +114,5 @@ setup(name=name,
     """,
     test_suite='tests',
     test_loader='trytond.test_loader:Loader',
+    use_2to3=True,
     )
diff --git a/tox.ini b/tox.ini
index e9d2876444..e2a064851d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,10 +1,10 @@
 [tox]
-envlist = py27-{sqlite,postgresql,mysql},pypy-{sqlite,postgresql}
+envlist = {py27,py33,py34,py35}-{sqlite,postgresql,mysql},pypy-{sqlite,postgresql}
 
 [testenv]
 commands = {envpython} setup.py test
 deps =
-    py27-postgresql: psycopg2 >= 2.0
+    {py27,py33,py34,py35}-postgresql: psycopg2 >= 2.0
     pypy-postgresql: psycopg2cffi >= 2.5
     mysql: MySQL-python
 setenv =