diff --git a/htdocs/core/class/html.form.class.php b/htdocs/core/class/html.form.class.php
index 05b976ad4d2..71b7b42fdcd 100644
--- a/htdocs/core/class/html.form.class.php
+++ b/htdocs/core/class/html.form.class.php
@@ -1225,6 +1225,12 @@ class Form
                         $disabled=' disabled';
                     }
 
+					if (!empty($conf->global->MAIN_SHOW_FACNUMBER_IN_DISCOUNT_LIST) && !empty($obj->fk_facture_source))
+					{
+						$tmpfac = new Facture($this->db);
+						if ($tmpfac->fetch($obj->fk_facture_source) > 0) $desc=$desc.' - '.$tmpfac->ref;
+					}
+
                     print '<option value="'.$obj->rowid.'"'.$selectstring.$disabled.'>'.$desc.' ('.price($obj->amount_ht).' '.$langs->trans("HT").' - '.price($obj->amount_ttc).' '.$langs->trans("TTC").')</option>';
                     $i++;
                 }