diff --git a/htdocs/contact.class.php b/htdocs/contact.class.php
index 17d4722118f..6fd6b3f71d4 100644
--- a/htdocs/contact.class.php
+++ b/htdocs/contact.class.php
@@ -165,7 +165,7 @@ class Contact
     {
 
       $sql = "UPDATE llx_socpeople SET ";
-      $sql .= " birthday='".$db->idate($this->birthday)."'";
+      $sql .= " birthday='".$this->db->idate($this->birthday)."'";
       $sql .= " WHERE idp=$id";
 
       $result = $this->db->query($sql);