diff --git a/addons/delivery/models/stock_picking.py b/addons/delivery/models/stock_picking.py
index f839915a48d..be94eecfc51 100644
--- a/addons/delivery/models/stock_picking.py
+++ b/addons/delivery/models/stock_picking.py
@@ -164,7 +164,8 @@ class StockPicking(models.Model):
         if self.carrier_id.free_over and self.sale_id and self.sale_id._compute_amount_total_without_delivery() >= self.carrier_id.amount:
             res['exact_price'] = 0.0
         self.carrier_price = res['exact_price']
-        self.carrier_tracking_ref = res['tracking_number']
+        if res['tracking_number']:
+            self.carrier_tracking_ref = res['tracking_number']
         order_currency = self.sale_id.currency_id or self.company_id.currency_id
         msg = _("Shipment sent to carrier %s for shipping with tracking number %s<br/>Cost: %.2f %s") % (self.carrier_id.name, self.carrier_tracking_ref, self.carrier_price, order_currency.name)
         self.message_post(body=msg)