diff --git a/addons/stock/stock.py b/addons/stock/stock.py
index 5259c2b0e0b..11d72428ab8 100644
--- a/addons/stock/stock.py
+++ b/addons/stock/stock.py
@@ -743,13 +743,18 @@ class stock_picking(osv.osv):
                 tax_ids = self._get_taxes_invoice(cursor, user, move_line, type)
                 account_analytic_id = self._get_account_analytic_invoice(cursor,
                         user, picking, move_line)
+                
+                #set UoS if it's a sale and the picking doesn't have one
+                uos_id = move_line.product_uos and move_line.product_uos.id or False
+                if not uos_id and type in ('out_invoice', 'out_refund'):
+                    uos_id = move_line.product_uom.id
 
                 account_id = self.pool.get('account.fiscal.position').map_account(cursor, user, partner.property_account_position, account_id)
                 invoice_line_id = invoice_line_obj.create(cursor, user, {
                     'name': name,
                     'origin': origin,
                     'invoice_id': invoice_id,
-                    'uos_id': move_line.product_uos.id,
+                    'uos_id': uos_id,
                     'product_id': move_line.product_id.id,
                     'account_id': account_id,
                     'price_unit': price_unit,
diff --git a/addons/stock/stock_view.xml b/addons/stock/stock_view.xml
index 2f6eb80fd87..382a8f87bba 100644
--- a/addons/stock/stock_view.xml
+++ b/addons/stock/stock_view.xml
@@ -1241,6 +1241,7 @@
                     <field colspan="4" name="product_id" select="1"/>
                     <field name="product_qty" select="2" on_change="onchange_quantity(product_id, product_qty, product_uom, product_uos)"/>
                     <field name="product_uom" select="2"/>
+                    <field name="product_uos" select="2"/>
                     <field colspan="4" name="name" select="2"/>
                     <field name="date"/>
                     <field name="date_planned"/>