diff --git a/addons/mrp/models/mrp_production.py b/addons/mrp/models/mrp_production.py
index cfd8679ed0b..ab6d498a4a0 100644
--- a/addons/mrp/models/mrp_production.py
+++ b/addons/mrp/models/mrp_production.py
@@ -1389,8 +1389,8 @@ class MrpProduction(models.Model):
                         new_moves_vals.append(move_vals[0])
                 new_moves = self.env['stock.move'].create(new_moves_vals)
             backorders |= backorder_mo
-            for wo in backorder_mo.workorder_ids:
-                wo.qty_produced = 0
+            for old_wo, wo in zip(production.workorder_ids, backorder_mo.workorder_ids):
+                wo.qty_produced = max(old_wo.qty_produced - old_wo.qty_producing, 0)
                 if wo.product_tracking == 'serial':
                     wo.qty_producing = 1
                 else: