1) The basic idea: you can’t “just use” a new surname

In Philippine law, a person’s legal name is the name reflected in the civil registry (birth record) and as issued by the PSA. Government agencies (passport, SSS, PhilHealth, banks, schools, PRC, etc.) generally require that your surname match your PSA record.

So, for an adult who wants to change their surname to the father’s surname, the correct process depends on why your current PSA record does not already carry your father’s surname.

2) Start here: identify your legal situation

Most adult “change to father’s surname” requests fall into one of these categories:

A. You are illegitimate (parents not married at conception/birth) and your PSA record shows your mother’s surname

This is the most common scenario. The usual route is administrative under R.A. 9255 (which amended Article 176 of the Family Code), if your father has acknowledged you (or can validly acknowledge you).

B. You are legitimate, but your record still shows your mother’s surname (or has errors)

This is less common and usually indicates a registration issue (e.g., wrong entries, late registration complications). This often requires a court case (commonly under Rule 108 and/or Rule 103, depending on what must be corrected).

C. Your parents later married and you were legitimated

If your parents were not married when you were born but later married (and no legal impediment existed), you may have become legitimated by operation of law. You then typically pursue annotation of legitimation and related corrections/updates with the civil registry (sometimes administrative; sometimes judicial if records are disputed or incomplete).

D. You were adopted (or have an adoption decree)

Your surname should follow the adoption decree, and the civil registry is updated based on that decree.

E. You simply want your father’s surname by preference

If your request is not anchored on recognized filiation, legitimation, or correction of an entry, you are usually looking at a judicial change of name (Rule 103), which courts grant only for proper and compelling reasons, not mere convenience.

3) The fastest common route: R.A. 9255 (Illegitimate child using father’s surname)

3.1 What R.A. 9255 does—and does not do

It allows an illegitimate child to use the father’s surname if paternity is acknowledged/established in the manner required by law.

It does not automatically:

make you legitimate,
change custody rules retroactively,
give you legitimate-child inheritance status, or
erase the fact of illegitimacy in law.

Your civil status remains illegitimate unless legitimation/adoption applies. Inheritance rights generally remain those of an illegitimate child (as defined by law), even if you use the father’s surname.

3.2 Who signs the “Affidavit to Use the Surname of the Father” (AUSF)?

For adults, the child (you) generally signs the AUSF. For minors, the mother commonly signs on the child’s behalf.

3.3 Core requirements (typical)

Requirements vary by Local Civil Registry (LCR), but commonly include:

PSA Birth Certificate (copy)
Valid IDs (and sometimes photos) of the affiant (you)
Proof of paternity/acknowledgment, such as:
- Father’s signature on the birth certificate at registration; or
- Affidavit of Acknowledgment / Admission of Paternity executed by the father; or
- Other documents acceptable under the rules on proving filiation (the LCR may require a specific form/document).
AUSF (notarized)
Payment of LCR fees for filing/annotation and endorsements/transmittals

Practical note: If your father is not named on the birth record at all, many LCRs require an Acknowledgment/Admission of Paternity first (or simultaneously), because the AUSF is about using the surname and typically presupposes legally recognized paternity.

3.4 Step-by-step process (typical flow)

Get your PSA Birth Certificate and read the entries carefully (child’s surname, father’s name field, remarks, etc.).
Prepare the required affidavits:
- AUSF (you execute as an adult); and
- If needed, Affidavit of Acknowledgment/Admission of Paternity (father executes).
Notarize the affidavit(s).
File with the Local Civil Registry where your birth was registered (some LCRs also accept through the city/municipality where you currently reside, but many prefer/require filing where registered).
The LCR processes the request and coordinates annotation and endorsement/transmittal to the PSA system.
After processing, request an updated PSA Birth Certificate reflecting the annotation and your father’s surname usage.

3.5 Timelines

Processing time depends on the LCR’s workload and transmittal to PSA. Expect that it may take weeks to months, especially where endorsements or revalidation/transmittal steps are involved.

3.6 Middle name issue (important)

In the Philippines:

A legitimate child traditionally has a middle name (mother’s maiden surname).
An illegitimate child generally has no middle name in the civil registry sense.

If you are an illegitimate child who uses the father’s surname under R.A. 9255, you may still not be entitled to use the mother’s maiden surname as a “middle name” in the same way legitimate children do. How this appears on IDs can vary by agency formatting, but the birth record typically governs.

4) When R.A. 9255 is not enough: you may need a court case

4.1 If paternity is disputed or not legally acknowledged

If your father refuses to acknowledge paternity or there is no legally acceptable proof, you may need a court action to establish filiation/paternity. Once paternity is judicially recognized, you can pursue the appropriate civil registry corrections/annotations.

This can become evidence-heavy (documents, witnesses, sometimes DNA testing if ordered/accepted within the rules and circumstances).

4.2 If your birth record needs “substantial” correction (Rule 108)

If what you need is not a simple clerical fix but a change affecting civil status, legitimacy, filiation entries, or other substantial matters, courts often require a petition under Rule 108 (Correction/Cancelation of Entries), typically with notice to interested parties and participation by the government through the prosecutor/OSG processes.

Examples that often push matters toward Rule 108 (or combined remedies):

correcting legitimacy status (legitimate/illegitimate),
correcting parentage entries,
removing/adding a parent entry in a way that is not purely clerical,
resolving conflicting records.

4.3 If you want a new surname mainly by preference (Rule 103)

A petition for Change of Name (Rule 103) is filed in the Regional Trial Court where you reside. It requires:

a verified petition,
publication in a newspaper of general circulation (typically once a week for three consecutive weeks),
a court hearing,
proof that you have proper and compelling reason and that the change will not prejudice public interest or enable fraud.

Courts are cautious about surname changes, because names are tied to identity, public records, and legal accountability.

Rule of thumb: If your reason is essentially “I want to carry my father’s surname” but the civil registry/filial basis is unclear or disputed, the case may involve Rule 108 and/or a filiation case, not just Rule 103.

5) Legitimation: if your parents later married

If your parents were not married when you were born but later married and there was no legal impediment at the time of conception (e.g., neither was validly married to someone else), legitimation may apply.

Effect: the child becomes legitimate by operation of law, and civil registry entries are typically annotated. This often supports adopting the father’s surname as a matter of record.

Practical steps commonly involve:

submitting parents’ marriage certificate,
birth certificate,
affidavits or forms required by the LCR,
and requesting annotation of legitimation.

If records are inconsistent (names, dates, prior marriages, etc.), a court petition may be required.

6) Costs: what you should realistically budget

6.1 Administrative route (R.A. 9255 / AUSF)

Costs vary by locality and document needs, but typical expense buckets include:

PSA certificates (birth certificate, sometimes father’s documents if required): usually a few hundred pesos per copy
Notarization of AUSF and/or Acknowledgment of Paternity: commonly a few hundred to a couple thousand pesos depending on location and complexity
Local Civil Registry fees for filing/annotation/endorsement: often hundreds to a few thousand pesos depending on the city/municipality and whether endorsements/transmittals are involved
Optional: costs for extra certified true copies, photocopying, transport

Practical ballpark: Many straightforward R.A. 9255 filings end up in the low thousands to several thousand pesos, excluding special cases.

6.2 Judicial route (Rule 103 / Rule 108 / filiation cases)

Judicial processes are more expensive because they may involve:

Filing fees and legal research fees (court-based; varies)
Publication cost (often one of the biggest line items): commonly tens of thousands of pesos depending on the newspaper and location
Attorney’s fees (widely variable): can range from tens of thousands to hundreds of thousands depending on complexity, hearings, evidence, and location
Documentary expenses: certified copies, service of notices, transcripts, travel, etc.

Practical ballpark: A contested or multi-issue case can be significantly more expensive than an administrative AUSF route.

7) What changes after your surname is updated

Once your PSA birth record is updated/annotated and you are using your father’s surname legally, you usually need to update:

PhilSys (National ID)
Passport (DFA)
Driver’s license (LTO)
SSS, PhilHealth, Pag-IBIG
TIN/BIR records
Bank accounts, e-wallets, credit cards
School records, PRC records, employment files
Land titles/registrations (if any), insurance policies, HMOs

Expect each agency to ask for:

updated PSA birth certificate (annotated),
valid IDs,
and sometimes the affidavit/court order and a photocopy set.

8) Common pitfalls and how to avoid them

Pitfall 1: Filing AUSF without legally acceptable paternity proof

Fix: Ensure your father’s acknowledgment is documented in the form required. If paternity is not recognized legally, you may need a different legal route.

Pitfall 2: Assuming a surname change automatically changes legitimacy or inheritance status

Fix: R.A. 9255 is mainly about surname usage, not legitimation.

Pitfall 3: Trying to “correct” a surname through the wrong procedure

R.A. 9048 (and amendments) generally addresses clerical errors and first name changes, not ordinary surname changes by preference. Fix: For surname changes, expect R.A. 9255 (if applicable) or court action (Rule 103/108), depending on the facts.

Pitfall 4: Mismatched records across agencies

Fix: After PSA annotation, update systematically and keep certified copies.

9) Practical decision guide (quick)

If you are an adult and your PSA birth certificate shows your mother’s surname, ask:

Are my parents married to each other at my birth?

If yes but your record is wrong → likely Rule 108 or related correction route.
If no → you are likely illegitimate (unless later legitimated/adopted).

Is my father legally acknowledged on record or willing to acknowledge me?

If yes → explore R.A. 9255 (AUSF) administrative filing.
If no / disputed → you may need filiation/paternity proceedings first.

Did my parents later marry (and legitimation might apply)?

If yes → explore legitimation annotation (and corrections if needed).

Is the goal purely preference, not tied to filiation or correction?

Expect Rule 103 (harder; needs compelling grounds).

10) What to prepare before going to the Local Civil Registry or a lawyer

Bring and/or obtain:

PSA Birth Certificate (several copies)
Any document showing your father’s acknowledgment (if already existing)
Parents’ marriage certificate (if legitimation may apply)
Valid IDs
A written timeline of facts: birth registration details, who registered you, what documents exist, father’s involvement, and what exactly is wrong on the record

This lets the LCR or counsel quickly identify whether your case is straightforward administrative (AUSF) or judicial/substantial (Rule 108/103/filiation).

11) Key takeaway

For an adult in the Philippines who wants to change to the father’s surname, the “requirements and costs” hinge on one question:

Is your right to use your father’s surname supported by legally recognized filiation (acknowledgment/legitimation/adoption) and properly reflected—or correctable—in the civil registry?

If yes, the process can often be administrative (commonly via R.A. 9255 for illegitimate children).
If no, or the record problem is substantial or disputed, expect court proceedings (Rule 108/Rule 103 and sometimes a filiation case), with publication and substantially higher costs.

This article is for general legal information in the Philippine context and is not legal advice. For any case involving disputed paternity, conflicting records, or legitimacy/legitimation issues, a tailored assessment using your actual PSA/LCR entries is strongly advisable.