every sibling must bear the same surnames. Both surnames are equally important and having two surnames is obligation for any person in birth registrations, the use of them are mandatory for any official document. Exceptionally some people may have only one surname.

In Chile people never replace their surnames by the spouse's ones at marriage. Spouse's name adoption is not socially practiced and the possibility of so doing is not even contemplated by the law. Although a woman may socially use the marital conjunction de--a very rare practice