diff --git a/partner_vat_unique/README.rst b/partner_vat_unique/README.rst
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+.. image:: https://img.shields.io/badge/licence-AGPL--3-blue.svg
+   :target: http://www.gnu.org/licenses/agpl-3.0-standalone.html
+   :alt: License: AGPL-3
+
+
+==================
+Partner VAT Unique
+==================
+
+Module to make the VAT number unique for customers and suppliers. Will not
+consider empty VATs as duplicated.
+
+
+Installation
+============
+
+Will not check previous VAT duplicates, so it is recomended make sure there
+isn't any duplicated VAT before installation.
+
+
+Bug Tracker
+===========
+
+Bugs are tracked on `GitHub Issues
+<https://github.com/OCA/partner-contact/issues>`_. In case of trouble, please
+check there if your issue has already been reported. If you spotted it first,
+help us smash it by providing detailed and welcomed feedback.
+
+
+Maintainer
+----------
+
+.. image:: https://odoo-community.org/logo.png
+   :alt: Odoo Community Association
+   :target: https://odoo-community.org
+
+This module is maintained by the OCA.
+
+OCA, or the Odoo Community Association, is a nonprofit organization whose
+mission is to support the collaborative development of Odoo features and
+promote its widespread use.
+
+To contribute to this module, please visit https://odoo-community.org.
diff --git a/partner_vat_unique/__init__.py b/partner_vat_unique/__init__.py
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+++ b/partner_vat_unique/__init__.py
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+from . import models
diff --git a/partner_vat_unique/__manifest__.py b/partner_vat_unique/__manifest__.py
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+++ b/partner_vat_unique/__manifest__.py
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+# -*- coding: utf-8 -*-
+# Copyright 2017 Grant Thornton Spain - Ismael Calvo <ismael.calvo@es.gt.com>
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+{
+    "name": "Partner VAT Unique",
+    "version": "10.0.1.0.0",
+    "category": "Customer Relationship Management",
+    "website": "https://github.com/OCA/partner-contact",
+    "author": "Grant Thornton S.L.P, Odoo Community Association (OCA)",
+    "license": "AGPL-3",
+    "application": True,
+    "installable": True,
+    "depends": ["base"],
+}
diff --git a/partner_vat_unique/i18n/es.po b/partner_vat_unique/i18n/es.po
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+++ b/partner_vat_unique/i18n/es.po
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+# Translation of Odoo Server.
+# This file contains the translation of the following modules:
+#   * partner_vat_unique
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Odoo Server 10.0+e\n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2017-11-29 11:43+0000\n"
+"PO-Revision-Date: 2017-11-29 11:43+0000\n"
+"Last-Translator: <>\n"
+"Language-Team: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: \n"
+"Plural-Forms: \n"
+
+#. module: partner_vat_unique
+#: code:addons/partner_vat_unique/models/res_partner.py:22
+#, python-format
+msgid "The VAT must be unique per partner!"
+msgstr "¡El NIF debe de ser único por empresa!"
+
diff --git a/partner_vat_unique/models/__init__.py b/partner_vat_unique/models/__init__.py
new file mode 100644
index 000000000..91fed54d4
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+++ b/partner_vat_unique/models/__init__.py
@@ -0,0 +1 @@
+from . import res_partner
diff --git a/partner_vat_unique/models/res_partner.py b/partner_vat_unique/models/res_partner.py
new file mode 100644
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+++ b/partner_vat_unique/models/res_partner.py
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+# -*- coding: utf-8 -*-
+# Copyright 2017 Grant Thornton Spain - Ismael Calvo <ismael.calvo@es.gt.com>
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+
+from odoo import api, models, _
+from odoo.exceptions import ValidationError
+
+
+class ResPartner(models.Model):
+    _inherit = 'res.partner'
+
+    @api.constrains('vat')
+    def _check_vat_unique(self):
+        for record in self:
+            if record.parent_id:
+                continue
+            results = self.env['res.partner'].search([
+                ('parent_id', '=', False),
+                ('vat', '=', record.vat),
+                ('id', '!=', record.id)
+            ])
+            if results:
+                raise ValidationError(_(
+                    "The VAT %s already exists in another "
+                    "partner.") % record.vat)
diff --git a/partner_vat_unique/static/description/icon.png b/partner_vat_unique/static/description/icon.png
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diff --git a/partner_vat_unique/tests/__init__.py b/partner_vat_unique/tests/__init__.py
new file mode 100644
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+++ b/partner_vat_unique/tests/__init__.py
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+from . import test_vat_unique
diff --git a/partner_vat_unique/tests/test_vat_unique.py b/partner_vat_unique/tests/test_vat_unique.py
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+++ b/partner_vat_unique/tests/test_vat_unique.py
@@ -0,0 +1,23 @@
+# -*- coding: utf-8 -*-
+# Copyright 2017 Grant Thornton Spain - Ismael Calvo <ismael.calvo@es.gt.com>
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+
+from odoo.tests.common import SavepointCase
+from odoo.exceptions import ValidationError
+
+
+class TestVatUnique(SavepointCase):
+    @classmethod
+    def setUpClass(cls):
+        super(TestVatUnique, cls).setUpClass()
+        cls.partner = cls.env['res.partner'].create({
+            'name': 'Test partner',
+            'vat': 'ESA12345674'
+        })
+
+    def test_duplicated_vat_creation(self):
+        with self.assertRaises(ValidationError):
+            self.env['res.partner'].create({
+                'name': 'Second partner',
+                'vat': 'ESA12345674'
+            })