diff --git a/tryton/modules/product/message.xml b/tryton/trytond/trytond/modules/product/message.xml
index d77bc0e..d8b1f2f 100644
--- a/tryton/modules/product/message.xml
+++ b/tryton/modules/product/message.xml
@@ -24,5 +24,8 @@ this repository contains the full copyright notices and license terms. -->
         <record model="ir.message" id="msg_invalid_code">
             <field name="text">The %(type)s "%(code)s" for product "%(product)s" is not valid.</field>
         </record>
+        <record model="ir.message" id="msg_product_code_unique">
+            <field name="text">Code of active product must be unique.</field>
+        </record>
     </data>
 </tryton>
diff --git a/tryton/modules/product/product.py b/tryton/trytond/trytond/modules/product/product.py
index 7207c02..559329e 100644
--- a/tryton/modules/product/product.py
+++ b/tryton/modules/product/product.py
@@ -7,12 +7,13 @@ from importlib import import_module

 import stdnum
 import stdnum.exceptions
-from sql import Null, Column
+from sql import Null, Column, Literal
+from sql.operators import Equal

 from trytond.i18n import gettext
 from trytond.model import (
     ModelView, ModelSQL, Model, UnionMixin, DeactivableMixin, sequence_ordered,
-    fields)
+    Exclude, fields)
 from trytond.pyson import Eval
 from trytond.transaction import Transaction
 from trytond.pool import Pool
@@ -238,6 +239,14 @@ class Product(

         super(Product, cls).__setup__()

+        t = cls.__table__()
+        cls._sql_constraints = [
+            ('code_exclude', Exclude(t, (t.code, Equal),
+                    where=(t.active == Literal(True))
+                    & (t.code != '')),
+                'product.msg_product_code_unique'),
+            ]
+
         for attr in dir(Template):
             tfield = getattr(Template, attr)
             if not isinstance(tfield, fields.Field):