Short answer. From your birth. The Family Code says the effects of legitimation retroact to the time of the child's birth, so the law treats you as having been legitimate all along rather than as becoming legitimate on the day your parents married.
What the law says
The effects of legitimation shall retroact to the time of the child's birth.
Family Code, Article 180 — Legitimation Retroacts to Birth. Read the full provision →
One sentence, and it is doing a lot
The provision reads in full: the effects of legitimation shall retroact to the time of the child's birth. It does not say the child becomes legitimate when the parents marry, nor that the status takes effect once the registry is corrected. It reaches backwards and rewrites the whole of the child's legal history. The wedding is the event that triggers legitimation, but it is not the date the rights begin. That distinction is the entire content of the article, and it decides a surprising number of practical questions years later.
Where retroactivity actually bites
Consider a grandparent who died between the child's birth and the parents' marriage. If legitimation only took effect from the wedding, the child would have been illegitimate at the moment that succession opened. Because the effects retroact to birth, the status is taken to have existed then. The same logic applies to the surname the child is entitled to bear, to claims for support covering earlier periods, and to any right whose existence is measured by status at a past date. Retroactivity is not a formality; it is what makes the status worth having.
What retroactivity does not undo
It is a rule about status, not a licence to reopen everything that was settled in the meantime. Rights already acquired by other people in good faith, and matters closed by final judgment or by the running of a prescriptive period, are not swept away because a status was later perfected. The realistic way to read the article is that from the moment legitimation operates, the child is treated as legitimate from birth going forward, while transactions long since completed on the old footing are not automatically undone. That boundary is where the litigation tends to be.
Fix the record, then rely on it
Retroactive effect in law is of limited use if the civil registry still shows the old entry, because the entry is what everyone in practice reads. The documents that matter are the child's birth certificate, the parents' marriage certificate and whatever the registry now reflects following legitimation. Get certified copies of all three and check that they are consistent with each other. If they are not, deal with that before making a claim to support, a surname or a share in an estate, and bring the whole set to a lawyer at once.
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.
- Republic of the Philippines vs. Linney Jean L. Tangarorang and Ramer R. Tangarorang, G.R. No. 272006, February 5, 2025 — read the decision on LawPhil →
- Republic of the Philippines vs. Oliver M. Boquiren and Roselyn M. Boquiren, Duly Represented By Her Mother Rosalinda B. Macaraeg, G.R. No. 250199, February 13, 2023 — read the decision on LawPhil →