(Philippine legal context; practical guide; general information only—not legal advice.)

Removing a father’s surname from a child’s records in the Philippines is often misunderstood as “just executing an affidavit.” In reality, whether an affidavit is enough depends entirely on why the child is using the father’s surname in the first place (legitimate vs. illegitimate; acknowledged vs. not; administrative entry vs. legal status). In many situations, an affidavit alone cannot change a civil registry entry—you may need an administrative petition with the Local Civil Registrar/PSA or a court case.

This article explains the governing rules, when an affidavit can work, when it cannot, and the typical procedures and consequences.

1) Start with the most important distinction: legitimate vs. illegitimate

A. If the child is legitimate

A legitimate child generally bears the father’s surname as a legal consequence of legitimacy and filiation. Removing the father’s surname usually cannot be done by affidavit because it effectively alters filiation/legitimacy or the legal name established by law, and will typically require court action (often alongside a deeper issue like annulment of filiation, adoption, or a judicial change of name).

B. If the child is illegitimate

An illegitimate child’s default surname is the mother’s surname. The child may use the father’s surname only under specific conditions, typically when the father has recognized the child (and the legal requirements for using the father’s surname were satisfied). In this area, limited administrative paths may exist, and affidavits may be part of the documentation—but they are not automatically self-executing.

2) Key Philippine laws and rules involved (plain-English map)

You’ll encounter these legal “buckets”:

A. Substantive family law (who the parents are; whose surname applies)

Family Code principles on legitimacy, illegitimacy, and filiation
The rule that an illegitimate child generally uses the mother’s surname, unless recognized and allowed to use the father’s surname under the law

B. Administrative correction laws (fixing certain civil registry entries without going to court)

RA 9048 (administrative correction of clerical/typographical errors and first name/nickname)
RA 10172 (expanded certain administrative corrections to day/month of birth and sex under conditions)

Important: These laws help with certain corrections. They do not generally allow a Local Civil Registrar to rewrite parentage/filiation just because someone signs an affidavit.

C. Court processes (when what you’re changing is substantial)

Rule 103 (Change of Name—judicial)
Rule 108 (Cancellation/Correction of Entries—judicial; used for “substantial” corrections such as legitimacy/filiation-related matters)

3) “Removing the father’s surname” can mean different things

Before choosing a remedy, identify what exactly you are trying to change:

The child’s registered name on the birth certificate (the “name” field)
The father’s details on the birth certificate (name, nationality, etc.)
The child’s status of filiation (whether the father is legally recognized)
The child’s surname use in non-civil documents (school records, IDs, passport) even if the birth certificate stays the same
Correcting an error vs. changing a validly recorded fact

Each has different requirements.

4) When an affidavit might be relevant (and when it’s not enough)

A. Situations where affidavits commonly appear (supporting documents)

Affidavits are often used to:

Explain facts and history (recognition, use of surname, custody situation)
Show consent or non-consent (where legally relevant)
Support an administrative petition (where the law permits)
Establish identity consistency (for records harmonization)

But affidavits generally do not override a birth certificate entry by themselves.

B. Situations where people often think an affidavit is enough—but it usually isn’t

“The father disappeared / never supported the child—so we’ll remove his surname.” Non-support does not automatically change the child’s registered surname.
“We broke up; I want the child to use my surname again.” A preference change is often treated as a change of name requiring proper process.
“The father isn’t the real father.” That’s a filiation/paternity issue—typically substantial and court-driven.

5) The most common real-world scenarios and the usual legal route

Scenario 1: Illegitimate child used father’s surname because father recognized the child; now mother wants the child to revert to mother’s surname

This is one of the most common situations.

Key question: How did the child end up using the father’s surname on the birth certificate? Often, it’s because the father recognized the child and the requirements for use of the father’s surname were complied with.

Typical reality:

If the surname use was properly recorded and recognized, reverting can be treated as a change of name or substantial correction, often requiring court action, unless there is a specific administrative mechanism applicable in your locality under PSA/civil registrar guidelines.
In practice, Local Civil Registrars may require a formal petition and may deny a purely affidavit-based request if it changes a substantive entry.

What an affidavit does here: It may serve as a supporting document (narrating facts, custody, best interest, child’s use of surname), but it’s rarely the only requirement.

Scenario 2: Illegitimate child is using the father’s surname in school/IDs, but the birth certificate is still in the mother’s surname

Here, you may not be trying to “remove” anything from the civil registry—you may be trying to align records.

Two directions:

If you want everything to match the birth certificate, you usually update school/other records to the birth certificate name (often easiest).
If you want the birth certificate to match the used name, that may require recognition/legal steps or judicial change of name depending on facts.

Affidavit use: Common for schools/agencies as a temporary explanation, but institutions vary and may still require PSA birth certificate as the controlling document.

Scenario 3: Child is legitimate (or treated as such in records), but mother wants to remove father’s surname due to separation/annulment/abandonment

Separation, abandonment, or marital breakdown does not automatically change the child’s surname. If legitimacy/filiation remains, surname change is usually a judicial change of name matter and assessed under standards like proper and reasonable cause and best interest of the child.

Affidavit use: Supporting evidence only; not a substitute for court authority.

Scenario 4: The father’s name is on the birth certificate but mother claims it was inserted incorrectly or without proper basis

If the entry is truly erroneous or improper, the remedy may be:

Judicial correction/cancellation (Rule 108) for substantial entries; and/or
Addressing the underlying recognition/filiation issue

Affidavit use: Part of evidence, but the change generally requires due process because it affects the status and rights of the child and the putative father.

Scenario 5: The goal is to remove the father’s surname because the father is not biologically the father

This is effectively a paternity/filiation dispute. Expect:

Court proceedings; and
Higher scrutiny because it impacts identity, legitimacy/illegitimacy, support obligations, and inheritance rights.

Affidavit use: Not sufficient on its own.

6) Administrative vs. judicial: how to know which track you’re in

A. Administrative track (Local Civil Registrar / PSA) is usually for:

Clerical/typographical errors
Certain changes allowed by law (e.g., first name/nickname under conditions)
Some record annotations within the bounds of delegated authority

If your request changes who the father is, whether the child is recognized, or a substantive name change, it often goes beyond administrative authority.

B. Judicial track (court) is commonly needed when:

The change is substantial (filiation/legitimacy-related entries)
You’re seeking a full change of surname absent a purely clerical basis
There is or may be an opposing party (e.g., father contests)

7) What an “Affidavit for Removing Father’s Surname” usually looks like (and what it can’t promise)

There isn’t one universal affidavit that automatically works nationwide. However, affidavits used in this context typically contain:

Common contents

Child’s complete name as currently registered
PSA birth certificate details (Registry No., date/place of birth, Local Civil Registry)
Mother’s details and custody facts
Father’s details (as reflected in records) and relevant background
How the father’s surname came to be used (recognition, documents signed, timing)
Why a change is sought (consistent use, welfare/best interest, confusion, safety concerns)
Statement of truth and undertakings (e.g., to publish if required by court, to notify parties if directed)

Attachments often requested (varies by case)

PSA Birth Certificate (security paper copy)
Valid IDs of affiant(s)
Proof of custody/guardianship if relevant
Proof of the child’s consistent use of a surname (school records, medical records, baptismal certificate, etc.)
Recognition documents (if any)
If court case: additional procedural requirements (publication, notices, etc.)

What it cannot lawfully do by itself

Order the Local Civil Registrar/PSA to change a substantial entry without the proper petition/order
Extinguish the father’s obligations (support) or the child’s rights (inheritance) by mere declaration
Decide filiation disputes

8) Best interest of the child: the practical “north star”

Even when a change is legally possible, decision-makers often look at:

The child’s age and capacity to understand
Length and consistency of surname use
Risk of confusion, stigma, or harm
Stability and welfare (school, medical, community identity)
Presence/absence of paternal relationship (relevant but not automatically decisive)
Whether the request is to avoid lawful obligations (courts are wary)

For older minors, the child’s own preference may matter more in practice.

9) Effects and consequences people overlook

A. Support and parental authority

Changing the surname does not automatically terminate:

A father’s duty to support (if legally established)
Parental authority rules (which depend on legitimacy/recognition and custody orders)

B. Inheritance and legitimacy implications

If the change is tied to removing recognition or altering filiation, it can affect:

Successional rights
Legal standing as child/heir
Future claims

C. Passports, travel, and government IDs

Different agencies may require:

The PSA birth certificate as controlling proof of identity
Additional documents if names differ across records

D. Future corrections get harder

Once records diverge, harmonizing later can be more complicated and expensive.

10) Practical step-by-step approach (safest sequence)

Step 1: Get the child’s PSA birth certificate and identify what exactly is recorded

Check:

The child’s full name (including surname)
Whether the father is named
Notes/annotations, if any

Step 2: Determine the child’s legal status and basis of surname use

Legitimate or illegitimate?
Was there recognition?
Was the surname use recorded in a way that suggests a substantive legal act?

Step 3: Start with the Local Civil Registrar inquiry (administrative possibility screening)

Even if you expect court action, the Local Civil Registrar can often tell you:

Whether the requested correction is within administrative authority
What documentary requirements they apply
Whether they will require a court order

Step 4: If the change is substantial, prepare for judicial remedies (Rule 103 / Rule 108)

A lawyer typically helps here because:

Pleadings, jurisdiction, publication/notice, and evidence rules matter
Mistakes cause dismissal or delays

Step 5: After the correct civil registry change, harmonize other records

Schools, PhilHealth, banks, passports, etc., often follow once the PSA record is corrected/updated.

11) Common pitfalls

Filing the wrong remedy (administrative when court is required, or vice versa)
Treating a substantial change as a “clerical error”
Not addressing notice/participation of affected parties in court proceedings
Expecting surname change to erase legal fatherhood obligations/rights
Creating inconsistent identities across documents (school vs. PSA)

12) If you truly need an affidavit: a clean, realistic framing

If you are executing an affidavit for use in a petition or as supporting evidence, the safest way to title and word it is to avoid implying it is self-executing, e.g.:

“Affidavit of Explanation and Request for Reversion to Mother’s Surname”
“Affidavit of Discrepancy / Affidavit of One and the Same Person” (if dealing with mismatched records)
“Affidavit in Support of Petition for Change of Name / Correction of Entry”

The affidavit should say it is executed to support the proper petition or request, and that changes will be made only upon approval by the proper authority (civil registrar/PSA or court).

13) When to consult a lawyer (strongly recommended)

You should strongly consider counsel when:

The child is legitimate
The father is listed and recognition/filiation is contested
You need to remove or alter the father’s entries (not just surname)
You anticipate objection
You need Rule 103/108 filings

14) Bottom line

An affidavit alone is rarely enough to “remove the father’s surname” from a child’s PSA birth record.
The correct remedy depends on whether the matter is clerical (limited administrative correction) or substantial (often judicial).
For illegitimate children, surname use and reversion can be more nuanced, but still often requires formal petitions and sometimes court orders.
Always treat the PSA birth certificate as the anchor record; change it properly first, then harmonize everything else.

If you want, you can paste (1) the child’s current PSA name format (no need for registry numbers), (2) whether the parents were married at birth, and (3) whether the father signed/recognized the child—then I can map the most likely correct legal track (administrative vs. Rule 103 vs. Rule 108) and what an affidavit should realistically be used for in that track.