Short answer. Possibly, but not under Article 366 anymore. That article's old rule for an acknowledged 'natural child' no longer applies — the Family Code now treats her as an illegitimate child, and the surname provision of the Family Code, as amended by Republic Act No. 9255, is what actually decides whether she may carry her father's surname today.
What the law says
A natural child acknowledged by both parents shall principally use the surname of the father. If recognized by only one of the parents, a natural child shall employ the surname of the recognizing parent.
Civil Code, Article 366 — Surname of an Acknowledged Natural Child. Read the full provision →
What Article 366 originally said
As enacted, Article 366 tied a child's surname to how she was recognized. A natural child acknowledged by both parents was to principally use the surname of the father; a child recognized by only one parent used that parent's surname instead. This was written for a specific category the old Civil Code recognized: a 'natural child,' meaning one born to parents who had no legal impediment to marrying each other at the time she was conceived — as distinct from other categories the Code separately addressed.
Why that category no longer exists
The Family Code abolished the Civil Code's sub-classes of children born outside marriage — the 'natural' child, the 'natural child by legal fiction,' and the rest — and replaced them with a single class: illegitimate children. That means the specific test Article 366 used, whether one or both parents acknowledged her, is no longer the legal hook for deciding a surname. Whatever her parents' particular history of recognition, the Family Code now asks a simpler question: was she conceived and born outside a valid marriage.
The rule that actually governs her surname today
Surnames for illegitimate children are now governed by the Family Code's own surname provision, as amended by Republic Act No. 9255. Under that framework, an illegitimate child's surname is not automatically her father's just because he acknowledged her — RA 9255 sets the conditions under which she may use his surname instead, with his own recognition of her as the central requirement. A parent asking whether a specific paperwork step or form satisfies those conditions should treat that as a question for the civil registrar or a lawyer, since the details sit in RA 9255 itself rather than in Article 366.
Why Article 366 still matters
Article 366 is not being explained here as dead trivia — it still surfaces in older birth certificates, older family records, and disputes over how a surname was assigned decades ago, where the 'natural child' label and its recognition-based rule are exactly what a registrar or court once applied. Reading it correctly, and knowing it has been superseded, is often the first step in sorting out whether an old entry matches current law or needs to be corrected to reflect it.
Cases citing this provision
These Supreme Court decisions cite the provision above. We list them so you can read them yourself; the summaries of what each decided are not ours to give.
- Emelita Basilio Gan vs. Republic of the Philippines, G.R. No. 207147, September 14, 2016 — read the decision on LawPhil →
- Republic of the Philippines vs. Trinidad R.A. Capote, G.R. No. 157043, February 2, 2007 — read the decision on LawPhil →
- Marissa A. Mossesgeld vs. Court of Appeals, et al, G.R. No. 111455, December 23, 1998 — read the decision on LawPhil →
Related provisions
- Civil Code, Article 366 — Surname of an Acknowledged Natural Child
- Civil Code, Article 367 — Surname of a Natural Child by Legal Fiction
- Civil Code, Article 360 — Council for the Protection of Children