diff --git a/addons/sale/sale.py b/addons/sale/sale.py
index 10b38d38a31..2492ca2a4a6 100644
--- a/addons/sale/sale.py
+++ b/addons/sale/sale.py
@@ -1226,7 +1226,7 @@ class sale_order_line(osv.osv):
                 if context.get('uom_qty_change', False):
                     values = {'price_unit': price}
                     for field in ['product_uos_qty', 'th_weight']:
-                        if result.get(field):
+                        if not result.get(field, False) is False:
                             values[field] = result[field]
                     return {'value': values, 'domain': {}, 'warning': False}
         if warning_msgs: