1) Legal Foundation

Primary rule (Family Code, Art. 176 as amended by R.A. 9255). An illegitimate child ordinarily uses the mother’s surname and is under the mother’s sole parental authority. R.A. 9255 (effective 19 March 2004) carves out an exception: an illegitimate child may use the father’s surname if the father expressly recognizes the child in the manner required by law. Using the father’s surname does not confer legitimacy and does not divest the mother of parental authority (unless specifically transferred by law or valid agreement consistent with the best interests of the child).

Key legal ideas to keep straight

Legitimacy vs. surname use. Surname use under R.A. 9255 is not legitimation; it is a naming right grounded on filiation/recognition.
Filiation/recognition. The father’s express recognition must be evidenced by specified instruments (see §3 below).
Best interests of the child. All actions by registrars and parents are guided by this standard.

2) Who May Apply and When

Child is a minor (below 18):
- Mother generally applies on the child’s behalf (default rule).
- Father may apply if the child is in his custody and the mother consents.
- Child 7–17 years old must personally consent to the change (usually via a separate affidavit of consent).
Child is already 18: The child applies personally.
Births registered before or after 19 March 2004: Both may be covered; the operative question is whether valid paternal recognition exists and whether the correct administrative path is followed.

3) What Counts as the Father’s “Express Recognition”

R.A. 9255 and its implementing rules accept any one of the following (the most common bases):

The Certificate of Live Birth (COLB) itself was signed by the father as informant or contains his admission (properly accomplished at the time of registration).
Affidavit of Admission of Paternity (AAP) executed by the father (usually notarized and in the prescribed civil registry form).
A Private Handwritten Instrument (PHI) of the father acknowledging the child (must bear his signature and clearly identify the child).
A public document where the father expressly recognizes the child (e.g., notarized acknowledgment).
A court judgment establishing filiation/paternity (e.g., compulsory recognition).

Practical tip: If the father’s name is blank on the birth record and none of the documents above exists, the registrar cannot annotate under R.A. 9255. The parent must first establish filiation (usually via court), then proceed with the administrative annotation.

4) The Core Instrument: AUSF (Affidavit to Use the Surname of the Father)

The Affidavit to Use the Surname of the Father (AUSF) is the statutory mechanism that triggers the change of surname on the PSA record after recognition is established. It is executed by:

The mother (for a minor child), or
The father with the mother’s consent (if the child is in his custody), or
The child (if already 18), with the necessary supporting proof of recognition.

The AUSF is filed with the Local Civil Registry (LCR) of the place where the birth was recorded (or where the AUSF is being processed under the LCR’s accepted routing rules), for transmittal to the Civil Registrar General (CRG)/PSA for annotation.

5) Documentary Requirements (Typical)

Exact checklists vary slightly per LCR, but expect:

Accomplished AUSF in the prescribed civil registry form.
Proof of paternal recognition (any one of §3): AAP / PHI / public document / father’s signed COLB / court decision.
Child’s PSA birth certificate (certified copy).
Valid IDs of executing parent(s) and, when applicable, of the child (7–17: for consent; 18+: for personal filing).
Affidavit of Consent of the Child (if 7–17).
Supporting documents for special cases (see §9).

Fees are assessed by the LCR and PSA; amounts and processing times vary by locality and workload.

6) Step-by-Step Administrative Process

A. When the father was already acknowledged on the birth record (or via AAP/PHI/public document):

Prepare: Secure the recognition document and the latest PSA birth certificate.
Execute AUSF: Mother (minor), father-with-consent (custody cases), or adult child (18+).
File at the LCR where the birth is registered (or accepted LCR for out-of-town filing).
Evaluation by LCR: Check completeness, formal validity, and identity of parties.
Transmittal to PSA/CRG: The LCR forwards approved papers for annotation.
Release: PSA issues a Birth Certificate with Annotation stating that the child is authorized to use the father’s surname pursuant to R.A. 9255.

B. When the father was not previously acknowledged:

Secure recognition first (father executes AAP or produces a qualifying PHI/public document; or obtain a court judgment of filiation).
Then follow Steps A(2)–A(6) using the AUSF.

7) What the PSA Annotation Looks Like and Its Effects

The original entry (usually showing the mother’s surname) remains, but the PSA-issued copy will carry a marginal annotation that the child is authorized to use the father’s surname under R.A. 9255, referencing the AUSF and supporting recognition document.
Effectivity is administrative and prospective in terms of record use; it does not change legitimacy.
Middle name rule (practice point):
- An illegitimate child who continues to use the mother’s surname typically has no middle name.
- Once the child validly uses the father’s surname under R.A. 9255, the mother’s surname generally becomes the middle name (as reflected in prevailing civil registration practice).
Parental authority: Stays with the mother, except when lawfully transferred or modified (e.g., by written agreement consistent with regulations or by court order).
Support and succession: Unaffected by the mere choice of surname; these flow from filiation, not the label of legitimacy.

8) Consent Rules Summarized

0–6 years old: No personal consent required; AUSF by the proper parent.
7–17 years old: Written consent of the child is required and attached to the AUSF.
18+ years old: The child must personally execute the AUSF; parental affidavits are no longer sufficient.

9) Special and Edge Cases

Father deceased: If he left a PHI or previously executed an AAP (or a court has recognized filiation), the AUSF can proceed using that proof. You cannot create a new acknowledgment on behalf of a deceased father.
Father abroad: AAP/AUSF may be executed before a Philippine Foreign Service Post (consulate/embassy) following authentication rules; documents are then routed to the LCR/PSA.
Born abroad (Report of Birth): Process the AUSF and recognition through the Philippine Foreign Service Post that handled the Report of Birth, for transmittal to the PSA.
Subsequent marriage of the parents: This may trigger legitimation under the Family Code (as amended), which is a different civil registry process. If legitimation applies and is completed, the child typically assumes the father’s surname by operation of law, rendering a separate AUSF unnecessary.
Mother or father is a minor/incapacitated: A legal guardian (or the unemancipated parent’s guardian) may need to participate, consistent with the rules on capacity and formalities.
Contested or withdrawn recognition: If recognition is disputed, or if the AUSF was procured by fraud/mistake, the remedy is judicial (cancellation/ correction), not an administrative recall by the LCR.
Father’s name blank on birth record; no recognition document: You generally need a court action to establish filiation before an AUSF can be entertained.
Existing court case on paternity/custody: Civil registry action should await or align with the court’s resolution to avoid conflicting entries.

10) Common Pitfalls (and How to Avoid Them)

Using AUSF without valid recognition: The registrar will deny or later nullify the annotation. Always secure AAP/PHI/public doc or court ruling first.
Missing child’s consent (7–17): Causes delays or rejection.
Notarization or consular form errors: Names, dates, and identifying details must exactly match the PSA birth record.
Assuming surname change = legitimacy: It does not; do not list “legitimate” in school or government forms unless a separate legal basis exists.
Skipping legitimation where applicable: If the parents later marry and legitimation is available, consider that route (it has different effects and entries).
Wrong venue: File at the correct LCR (or accepted out-of-town route) to avoid back-and-forth transmittals.

11) After the Annotation: Updating Records

Once the PSA issues a Birth Certificate with R.A. 9255 annotation, use that annotated copy to update:

School records, PhilHealth/SSS/GSIS, insurance policies
Passport, driver’s license, PRC/CSC records (follow each agency’s change-of-name protocols)
Bank and employment records, and other private registries

Carry the annotated PSA birth certificate and, where asked, the AUSF and recognition document (AAP/PHI/court order).

12) Quick Decision Map

Is there valid paternal recognition?

Yes → Proceed to AUSF and annotation.
No → Secure recognition (AAP/PHI/public doc) or file a court action to establish filiation.

Who will execute the AUSF?

Mother for minor (with child’s consent if 7–17).
Father (with mother’s consent) if the child is under his custody.
Child if 18+.

File at the correct LCR → PSA annotation → use annotated PSA birth certificate.

13) Frequently Asked Questions

Q1: Can the child later revert to the mother’s surname? Possible, but not by a simple new AUSF. Once the PSA has annotated R.A. 9255 usage, reversion typically requires judicial relief (change of name/cancellation) grounded on compelling reasons or best interests of the child.

Q2: Will the child now have the mother’s surname as middle name? In prevailing civil registry practice, yes—once the child validly uses the father’s surname under R.A. 9255, the mother’s surname is treated as middle name on future records.

Q3: Does the father gain parental authority by this change? No. The mother retains sole parental authority unless modified by law or a valid court/administrative process consistent with the child’s best interests.

Q4: Is DNA testing required? Not for AUSF if there is a qualifying recognition document (AAP/PHI/public doc or court ruling). DNA becomes relevant in contested paternity cases in court.

Q5: What if the LCR refuses due to form errors? Correct the defects (e.g., notarization, mismatched names, missing consent) and refile; substantial compliance is not enough for civil registry entries—exactness matters.

14) Practical Checklist (Ready-to-Use)

✅ Latest PSA birth certificate (child)
✅ AUSF (properly executed)
✅ Proof of recognition: AAP / PHI / public doc / father-signed COLB / court decision
✅ Child’s consent (if 7–17)
✅ Valid IDs of executing parent(s) and child (if applicable)
✅ Supporting papers for special scenarios (death of father, guardianship, foreign execution)
✅ LCR filing → PSA annotation → Replace working records with annotated PSA copy

Final Notes

The AUSF route is administrative and designed to be streamlined once express paternal recognition exists.
When in doubt about recognition, capacity, or disputes, seek judicial confirmation before approaching the LCR; it saves time and prevents conflicting records.
Keep certified true copies of all instruments used (AUSF, AAP/PHI, court orders) for future dealings with schools, banks, and government agencies.