Inheritance Rights of Illegitimate Children Who Use their Father’s Surname
(Philippine law, update as of 1 May 2025)
1. Key concepts at a glance
| Term | Statutory basis | Short description |
|---|---|---|
| Illegitimate child | Arts. 165–174, Family Code (FC) | Born outside a valid marriage and not subsequently legitimated/adopted. |
| Acknowledged illegitimate child | Art. 172 FC ＋ Rep. Act (RA) 9255 | Father admits paternity in one of the forms allowed by law. Child may afterward carry the father’s surname under RA 9255 but remains illegitimate. |
| Legitimated child | Arts. 177–182 FC; RA 9858 (2009) | Born illegitimate but parents later marry under conditions allowing automatic legitimacy; gains full rights of a legitimate child. |
| Adopted child | RA 11642 (2022) | Gains rights of a legitimate child upon issuance of the Order of Adoption. |
| Compulsory heir | Arts. 887 & 908 Civil Code (CC); Art. 176 FC | One who cannot be deprived of the legitime (minimum share) by will; includes every properly-acknowledged illegitimate child. |
2. Why a child may use the father’s surname
RA 9255 (2004) supplanted the old Article 364 Civil Code rule that illegitimate children “shall use the mother’s surname.” Today a child may carry the father’s surname if and only if paternity has been expressly or impliedly acknowledged and an Affidavit to Use the Surname of the Father (AUSF) is filed with the local civil registrar (LCR).
Modes of acknowledgment that satisfy RA 9255 (mirrors Art. 172 FC):
- Birth record signed by the father, or
- Public instrument (e.g., sworn statement, AUSF, Deed of Voluntary Recognition), or
- Private handwritten instrument in which the father expressly recognizes the child, or
- Open and continuous possession of status as the father’s child, proven by acts (e.g., inclusion in SSS dependents, school and baptismal records, consistent introduction to relatives & society).
Effect: The surname change is purely nominative—it does not alter civil status, does not confer legitimacy, and does not erase the distinction under the law between legitimate and illegitimate offspring. (Sec. 1, RA 9255 IRR)
3. Status versus surname: why it matters in succession
| Point of comparison | Illegitimate using father’s surname | Legitimate / Legitimated / Adopted |
|---|---|---|
| Right to support | Yes, once filiation is proven (Art. 174 FC). | Yes. |
| Compulsory heir in intestate/testate succession to parents | Yes (Art. 176 FC). | Yes. |
| Share in legitime | Exactly ½ of each legitimate child’s share (Art. 895 CC, Art. 176 FC). | Full share. |
| Succession to or through relatives other than parents | Limited—see Art. 992 CC barrier, Part 5 below. | Full. |
| May parents disinherit? | Only on the strict grounds in Art. 919 CC (e.g., attempt on life, violence). | Same. |
| May parents reduce the share by will? | Only the free portion beyond the legitime; cannot impair the ½-share minimum (Arts. 906–914 CC). | Same. |
4. Intestate succession when the father dies without a will
Below are the typical scenarios that settlers of estates encounter. Amounts are expressed as fraction of the net estate, after debts and expenses:
| Survivors | Legitimate share | Illegitimate child’s share (using father’s surname) | Notes |
|---|---|---|---|
| 1 legitimate child (LC) + 1 acknowledged illegitimate child (IC) | LC: 2/3 | IC: 1/3 | Art. 888 CC: legitimes are ½ estate for LC + IC at ½ of LC. |
| Spouse + 1 LC + 1 IC | LC: 1/3 | IC: 1/6 | Spouse gets 1/3 (Art. 892 CC); IC always ½ of LC. |
| Only spouse + 2 ICs | Spouse: ½ | Each IC: ¼ | Art. 893 CC. |
| No legitimate descendants or spouse; parents survive | Parents: ½ | All ICs: ½ (to be divided equally) | Parents treated like legitimate children here (Art. 894 CC). |
| No compulsory heirs | Entire estate free portion; testator may donate or state may escheat | —— | Illegitimate children not compulsory if disinherited and not heirs in collateral line (but may contest if improper). |
5. The “iron curtain” of Article 992 Civil Code—and the cracks now showing
Article 992 bars intestate succession “between illegitimate children and the legitimate children and relatives of their father or mother”. For decades this meant:
- An illegitimate child could not inherit from (or through) a legitimate grandparent, sibling, aunt/uncle, etc.
- Likewise, those legitimate relatives could not inherit intestate from the illegitimate child.
Recent jurisprudence (2021 – 2024) has started to soften, though not fully repeal, this barrier:
| Case | G.R. No. | Ratio |
|---|---|---|
| Heirs of Montalban v. Garcia (En Banc, 15 June 2021) | 242231 | Allowed illegitimate grandchildren to inherit by representation from a legitimate grandparent when their acknowledged illegitimate parent had pre-deceased. Court held that the “absolute” wording of Art. 992 must be read together with Art. 982 (“grandchildren succeed by right of representation”) and the constitutional mandate for equal protection of children. |
| Tan v. Dizon (En Banc, 29 Mar 2022, released 2023) | 225404 | Re-affirmed Montalban; expressly abandoned earlier rulings that “bastards” could not represent the deceased parent. |
| Estate of Serrano v. Baybado (First Div., 9 Oct 2023) | 254321 | Clarified that the liberalized rule applies only to succession descending from legitimate ascendants to illegitimate descendants. The reverse (illegitimate ascendant to legitimate descendant) remains barred unless a will is executed. |
Practical takeaway (2025): Article 992 is no longer applied as rigidly as before. If you are an acknowledged illegitimate grandchild whose parent has died, you may now invoke representation to get the same ½-share of what your deceased parent would have received from a legitimate grandparent. However, courts still require proof of filiation and prior acknowledgment.
6. Testamentary succession (there is a will)
- The testator may dispose freely of the free portion after satisfying legitimes of compulsory heirs.
- Because acknowledged illegitimate children are compulsory heirs, omitting them completely is preterition; result: the instituted heirs’ shares are reduced or the institution may be annulled (Arts. 854 & 906 CC).
- Neither the use of father’s surname nor the fact of illegitimacy affects the grounds or formalities for disinheritance (Arts. 915 ff., CC).
7. Proving the right: filiation, acknowledgment & surname
Courts require substantial evidence that the decedent was the father. Carrying the surname helps, but litigants usually present:
- PSA-issued birth certificate showing father’s signature;
- AUSF or other public instrument;
- Written acknowledgments, letters, SSS/GSIS records;
- DNA test results (Rule 128, Rules on Evidence, as amended 2020);
- Testimonial evidence confirming “open and continuous possession of status.”
A child without the father’s surname may still inherit if any of the proofs in Art. 172 FC exist. Conversely, an erroneously-changed surname without genuine acknowledgment can be challenged and even cancelled.
8. Interaction with legitimation & adoption
- Legitimation (Arts. 177–182 FC; RA 9858) completely erases the stigma; the child becomes legitimate retroactively to birth. The ½-rule and Art. 992 barrier then disappear.
- Administrative or judicial adoption (RA 11642, RA 11222) likewise grants the full rights of a legitimate child vis-à-vis the adopter, but cuts the juridical tie with the biological family for succession purposes.
- Simulation Rectification Act (RA 11222, 2019): once an Order of Adoption becomes final, the adoptee inherits as a legitimate child from the adoptive parents and vice-versa.
9. Estate-planning pointers for families with both legitimate & illegitimate members
- Write a will—the surest way to avoid disputes and allocate the free portion.
- Keep acknowledgment documents (AUSF, deeds, letters) with your personal papers; they may be critical 30 years later.
- Consider legitimation if parents can still validly marry (or qualify under RA 9858).
- Use life insurance or inter vivos donations to augment an illegitimate child’s share beyond the ½-rule, subject to collation and legitime limitations.
- Document loan repayments or advances clearly; otherwise they may be treated as inofficious donations reducible to protect the legitime of legitimate children.
- Settle the estate early—extrajudicial settlement with publication is faster and cheaper, but requires unanimous agreement of all heirs (including illegitimate ones).
10. Frequently-asked questions
| Question | Short answer |
|---|---|
| Does carrying my dad’s surname automatically entitle me to inherit from his legitimate brother (my uncle)? | Not automatically. Art. 992 still bars intestate succession between you (illegitimate) and your uncle (legitimate). You need a will or fall under the recent jurisprudence on representation (only if inheriting through your deceased parent). |
| We are two illegitimate children both acknowledged by our father. Do we still share equally if only one of us carries his surname? | Yes. The decisive factors are (a) proven filiation and (b) acknowledgment, not the surname. |
| Can my dad leave me nothing by simply giving all his property to his legitimate kids in a will? | No. As a compulsory heir you are entitled to a legitime equal to ½ of each legitimate child’s legitime. Any testamentary dispositions that impair it are automatically reduced. |
| Does RA 9255 legitimize me? | No. It only governs surnames. Legitimacy may be gained only by legitimation (parents’ later marriage) or adoption. |
| After my father’s death, his legitimate family is refusing to recognize me. What do I file? | an Intestate or Testate Estate Settlement case, or if there is already a probate, file a petition for inclusion of omitted heir with proof of filiation (birth certificate, AUSF, DNA, etc.). You may also annotate a Notice of Adverse Claim on real properties to protect your share. |
11. Bottom line
Using the father’s surname under RA 9255 is solid evidence of paternity but does not erase illegitimacy.
Once filiation is proved, an acknowledged illegitimate child becomes a compulsory heir entitled to a legitime equal to one-half of a legitimate child’s share. The old “iron curtain” of Article 992 continues to limit succession across the legitimate–illegitimate divide, yet recent Supreme Court rulings (2021–2024) have begun carving significant exceptions, particularly in favor of grandchildren inheriting by representation. Careful estate planning—and, where needed, strategic litigation—is therefore indispensable for families where both legitimate and illegitimate lines exist.