1. Primary – those who have precedence over and exclude other compulsory heirs
a. Legitimate children and descendants (legitimate), with respect to their legitimate parents and ascendants
2. Secondary – those who succeed only in the absence of the primary heirs
a. Legitimate parents and ascendants (legitimate), with respect to their legitimate children and descendants
3. Concurring – those who succeed together with the primary or the secondary compulsory heirs
a. Widow or widower (legitimate)
b. Illegitimate children and descendants (legitimate or illegitimate)