Changing a child’s surname in the Philippines is not a single, one-size-fits-all process. It depends on the child’s status under Philippine family law (legitimate, illegitimate, legitimated, adopted), and on whether the requested change is a permitted civil registry annotation (administrative) or a substantial change affecting civil status (often judicial or through a specific legal process like adoption).

This article explains the three most common “routes” people mean when they ask to change a child’s surname:

RA 9255 / “Use of the father’s surname” for an illegitimate child (administrative annotation; not legitimation)
Legitimation (child becomes legitimate because parents marry later and meet legal requirements)
Adoption (child becomes the adopter’s legitimate child; surname changes as a legal effect)

It also covers when you may need court action (e.g., Rule 103/108) and practical issues that frequently complicate surname changes.

Key Concepts: Name vs. Surname vs. Civil Status

1) A child’s surname is tied to legal status

Under the Family Code, the default surname rules track whether the child is legitimate or illegitimate, and whether there is later legitimation or adoption.

2) Changing a surname can be either:

Administrative/annotative: done by the Local Civil Registrar (LCR) through annotation or correction within the civil registry system, when the law expressly allows it (e.g., RA 9255 process; legitimation annotation; adoption documents implemented through the civil registry), or
Judicial/substantial: requires court proceedings when the change affects status, filiation, legitimacy, or involves contested facts.

3) “Using the father’s surname” is not the same as being “legitimated”

RA 9255 allows an illegitimate child to use the father’s surname under conditions, but the child remains illegitimate unless legitimated or adopted.

The Baseline Rules Under the Family Code

Legitimate child

A child is generally legitimate if conceived or born during a valid marriage, or in other situations recognized by law (e.g., within presumptions on legitimacy). A legitimate child customarily uses the father’s surname.

Illegitimate child (default rule)

Under Article 176 of the Family Code, an illegitimate child uses the mother’s surname and is under the exclusive parental authority of the mother (unless later modified by law/court in specific contexts). The father’s duties like support depend on proof of filiation/recognition, but parental authority over an illegitimate child is not automatically vested in the father.

Route 1: RA 9255 — Illegitimate Child Using the Father’s Surname

What RA 9255 did (in plain terms)

RA 9255 amended Article 176 so that an illegitimate child may use the father’s surname if the father has acknowledged the child (in the manner the law recognizes) and procedural requirements are met.

What RA 9255 does not do

It does not make the child legitimate.
It does not, by itself, transfer parental authority to the father.
It does not automatically settle custody or visitation.
It does not erase the mother’s rights or the child’s illegitimate successional status.

When RA 9255 is typically used

The birth certificate currently lists the child as illegitimate and using the mother’s surname, and you want the child to use the father’s surname.
The father is willing to recognize the child and execute the required instruments.

Legal core: recognition of filiation

RA 9255 hinges on the father’s recognition. Recognition is commonly shown through:

The father’s signature/participation in the child’s birth registration (where applicable), and/or
A public instrument acknowledging the child, or
Other recognized proof of acknowledgment accepted by civil registry rules.

In practice, the civil registrar often requires the Affidavit to Use the Surname of the Father (AUSF) and supporting proof of recognition.

The AUSF (Affidavit to Use the Surname of the Father)

AUSF is the standard administrative document used to implement RA 9255. It is filed with the Local Civil Registrar where the birth was registered (or through endorsed processes depending on location).

Who signs

If the child is below 18: commonly, the mother (as the parent with parental authority) participates/consents, and the father’s acknowledgment is evidenced; some civil registry processes require the father’s execution/appearance for acknowledgment instruments.
If the child is 18 or older: the child generally signs their own request/affidavit to use the father’s surname (subject to the registrar’s requirements).

Practical reality: requirements can be document-heavy. The central point is that the father must have legally recognized filiation, and the civil registry wants clear consent/intent consistent with the implementing rules.

Effects on the child’s “middle name”

In Philippine naming practice:

Legitimate child: middle name is typically the mother’s maiden surname.
Illegitimate child: traditionally no middle name is used in many records; the child uses the mother’s surname as last name.

When an illegitimate child uses the father’s surname under RA 9255, civil registry practice generally treats the mother’s surname as the child’s middle name (the mother’s maiden surname is used as middle name), while the father’s surname becomes the last name. The exact formatting is implemented through the annotated birth certificate.

Step-by-step overview (typical)

Confirm the birth record: Where was the birth registered? What appears on the certificate now (father’s entry, signatures, remarks)?
Prepare proof of recognition: birth record signatures and/or acknowledgment instrument as required.
Execute AUSF (and any required consent document).
File with the Local Civil Registrar: submit AUSF + supporting documents (IDs, birth certificate copies, acknowledgment proof, etc.).
Civil registry annotation: the record is annotated to reflect the use of the father’s surname.
PSA endorsement/issuance: after annotation is transmitted to the national repository, you request an updated PSA copy reflecting the change.

Common pitfalls under RA 9255

Father refuses to acknowledge: RA 9255 cannot be forced administratively. You may need a paternity/filiation case (to establish filiation) before surname use becomes legally available.
Disputed paternity: civil registrars typically will not implement a disputed change without proper legal basis; a court determination may be necessary.
Mother refuses consent for a minor child: depending on the exact registrar rules applied, lack of required consent can block the administrative route and push the dispute into court.
People assume it grants custody to the father: it doesn’t. Custody/parental authority are separate issues.
Reverting later: switching back from father’s surname to mother’s surname is often treated as a substantial change and may require court action, especially if it affects filiation-related entries.

Route 2: Legitimation — When Parents Later Marry

What legitimation is

Legitimation is a legal process under the Family Code where a child who was illegitimate at birth becomes legitimate by the subsequent valid marriage of the parents, provided that at the time of the child’s conception, the parents were not disqualified to marry each other.

The crucial requirement people miss: “No legal impediment” at conception

Legitimation generally requires that, when the child was conceived:

The parents could have legally married each other (no subsisting marriage to someone else, no prohibited relationship, etc.).

If there was a legal impediment (e.g., one parent was still married to another person at conception), legitimation is generally not available, even if they later marry—other remedies (like adoption) may be explored depending on facts.

Effects of legitimation

Once legitimated:

The child becomes legitimate (status changes).
The child’s rights align with legitimate children, including broader family-law consequences (succession, legitimacy presumptions, etc.).
The surname generally follows legitimate child rules (commonly the father’s surname).
Records are updated through civil registry annotation reflecting legitimation.

How legitimation is implemented (civil registry process)

Legitimation is typically reflected by:

The parents’ marriage certificate plus an affidavit/instrument for legitimation, filed with the Local Civil Registrar.
The birth record is annotated to show the child is legitimated by the subsequent marriage of the parents.

Practical step-by-step (typical)

Confirm eligibility (no impediment at conception; subsequent marriage valid).
Gather documents: child’s birth certificate, parents’ marriage certificate, IDs, and required legitimation forms/affidavits.
File at LCR: where the child’s birth was registered (or per registrar procedure).
Annotation and PSA update: obtain updated PSA documents reflecting legitimation.

Legitimation vs. RA 9255 in one sentence

RA 9255: changes surname usage for an illegitimate child (status stays illegitimate).
Legitimation: changes the child’s status to legitimate (and surname typically follows).

Route 3: Adoption — Domestic and Inter-Country (and the NACC System)

What adoption does

Adoption creates a legal parent-child relationship between adopter and adoptee, with the child generally becoming the adopter’s legitimate child by legal fiction and enjoying the rights of a legitimate child of the adopter(s).

Surname effect of adoption

As a general rule, adoption results in:

The child using the adopter’s surname, and
An amended civil registry record reflecting the adoptive parentage and name.

Modern Philippine adoption framework (high level)

Philippine adoption has historically been governed by statutes including:

Domestic adoption law (commonly associated with RA 8552, the Domestic Adoption Act), and
Inter-country adoption law (commonly associated with RA 8043).

In recent years, the Philippines moved toward an administrative adoption model under a central authority (the National Authority for Child Care or NACC) to streamline processes and reduce the burden of purely judicial proceedings. Depending on timing, category, and implementing rules, adoption may be administrative through NACC processes, with civil registry implementation following the adoption decree/certificate.

Who may be adopted / who may adopt (general considerations)

Requirements depend on the exact type of adoption, but typically involve:

Adopter’s legal capacity, age difference, moral character, emotional/financial capacity,
The child’s adoptability status (including required certifications for foundlings, abandoned, neglected children, etc., when applicable),
Required consents (biological parents when known/available, the child depending on age, spouse of adopter, etc.).

Typical adoption process flow (conceptual)

Initial application and eligibility screening
Home study / case study and supporting documents
Child matching and placement planning
Supervised trial custody / post-placement monitoring (where required)
Adoption approval (administrative certificate or court decree, depending on the applicable framework)
Civil registry implementation: issuance of an amended birth record and updated PSA documents

When adoption is the best (or only) route for surname change

Adoption is often considered when:

The child cannot be legitimated (e.g., there was an impediment at conception), and
A step-parent or another person wants to establish full parental rights and have the child carry their surname, or
There is a need to formalize a permanent parent-child relationship beyond surname usage.

Step-parent adoption and surname

Step-parent adoption is commonly used when:

A parent remarries, and the new spouse wants to adopt the child.
This typically results in the child using the step-parent/adopter’s surname and becoming the legitimate child of the adopter (with legal consequences that go beyond the name).

When You Can’t Use These Routes: Court-Based Name Changes (Rule 103 / Rule 108) and Administrative Corrections

Sometimes people ask, “Can we just change the surname?”—but the law distinguishes between:

Simple clerical corrections, and
Substantial changes affecting status or filiation.

A) Administrative correction laws (RA 9048 / RA 10172)

These laws allow administrative correction of certain entries in civil registry documents (commonly clerical/typographical errors, and certain specified entries like day/month of birth or sex under conditions).

However, changing a surname to reflect a different parent is usually not treated as a mere clerical correction. If what you’re really changing is tied to filiation or status, you’re typically pushed toward:

RA 9255 (if illegitimate and father recognized), or
Legitimation annotation, or
Adoption, or
A court proceeding if contested or not covered.

B) Rule 103 (Change of Name) and Rule 108 (Correction/Cancelation of Entries)

In broad strokes:

Rule 103 is used for a judicial petition for change of name.
Rule 108 is used for judicial correction/cancellation of civil registry entries and is often invoked when the correction is substantial (not merely clerical), particularly where civil status or filiation implications exist.

Courts scrutinize name-change petitions because names in civil registry records carry public interest consequences.

Common situations that end up in court

The alleged father disputes paternity but someone wants to use his surname.
A previous RA 9255 surname use is sought to be reversed, and the basis is not purely clerical.
The birth record contains entries that are legally problematic or require adjudication (e.g., conflicting parentage data).
There’s a need to establish or challenge filiation (paternity/maternity) as a prerequisite to surname change.

Comparing the Three Main Routes

RA 9255 (Illegitimate → father’s surname usage)

Who it’s for: illegitimate child with acknowledged father
What changes: surname usage (and often middle name formatting)
Status: child remains illegitimate
Where filed: Local Civil Registrar (administrative)
Key requirement: valid acknowledgment of filiation + required affidavits/consent

Legitimation (Illegitimate → legitimate by later marriage)

Who it’s for: parents later marry and had no impediment to marry at conception
What changes: civil status becomes legitimate; surname generally follows legitimacy
Status: becomes legitimate
Where filed: Local Civil Registrar (annotation)
Key requirement: subsequent valid marriage + eligibility at conception

Adoption (Child → adopter’s legitimate child)

Who it’s for: child to be legally integrated into adopter’s family
What changes: legal parentage, status, rights, surname
Status: treated as adopter’s legitimate child (with full legal effects)
Where filed: under adoption framework (now often administrative via NACC processes, with civil registry implementation afterward)
Key requirement: adoptability, adopter eligibility, consents, process compliance

Practical Questions People Ask (and Straight Answers)

“My child is illegitimate. Can we use the father’s surname even if we’re not married?”

Yes, potentially—RA 9255 is specifically about allowing an illegitimate child to use the father’s surname upon recognition and compliance with the civil registry procedure.

“If my child uses the father’s surname, does that mean the father gets custody?”

No. Surname use and parental authority/custody are different legal issues. For an illegitimate child, the mother generally retains parental authority, and custody disputes follow separate rules.

“We married later. Does the child automatically become legitimate?”

Not automatically. Legitimation requires eligibility, especially that there was no impediment to marry at the time of conception, plus proper civil registry annotation/documentation.

“Can my child change surname because I remarried?”

Not automatically. A step-parent’s surname generally requires step-parent adoption or another legally recognized route; mere remarriage does not change the child’s registered surname.

“Can we remove the father’s surname later?”

Sometimes, but it can be difficult. If the record has already been annotated and the change touches filiation or status, you may need a court proceeding unless the issue is truly clerical or falls within a specific administrative remedy.

“What if the father won’t acknowledge the child, but we want his surname?”

You generally can’t get it administratively under RA 9255 without acknowledgment. The usual path is a judicial action to establish filiation/paternity (fact-intensive) before any surname change based on that father can be legally supported.

A Practical Decision Guide

Start here: What is the child’s current status on record?

Child is illegitimate; father is willing to acknowledge → RA 9255 / AUSF route is usually the first option.
Parents were not married at birth, but later married—and there was no impediment at conception → Legitimation may be available (stronger status change than RA 9255).
Step-parent wants child to carry step-parent surname and be treated as their child → Adoption (often step-parent adoption), not RA 9255.
There is a dispute or the change affects status/filiation and isn’t squarely covered → Expect court involvement (often Rule 108 and/or related family actions).

Final Notes (to avoid expensive mistakes)

Don’t treat surname change as a mere “paper update.” It can imply (and sometimes legally require proof of) filiation, consent, and status changes.
RA 9255 is powerful but limited: it gives surname usage, not legitimacy.
Legitimation is narrow but transformative: it changes status, but only if legal conditions are met.
Adoption is the most comprehensive: it changes parentage and status, with lifetime legal effects.

If you want, tell me the child’s situation using these four facts—(1) parents married or not, (2) whether father acknowledged on the birth certificate or in a document, (3) child’s age, (4) what surname the child has now—and I’ll map the most likely lawful route and the usual document checklist for that route.