How Can An Illegitimate Child Use The Surname Of His or Her Father?

The birth certificate of an illegitimate child will most likely lack a middle name (for the child). This is because illegitimate children carry their mother’s last name as their last name unless the father authorizes the use of his last name on the child’s birth certificate. If an illegitimate child was assigned the mother’s last name at birth, can the father’s last name still be applied on the child’s birth certificate later on?

Read this.

Republic Act (RA) 9255 is a law that allows illegitimate children to use the surname of the father under the condition that the father has expressed his acknowledgement of the child. The law applies to all illegitimate children who were:

  • Born before or after the effectivity of RA 9255
  • Whose births were either registered or unregistered
  • And if registered, the child is using the mother’s last name as his last name.

What are the requirements needed so an illegitimate child can use his or her father’s last name?

  • Public or private documents that will prove that the child is recognized by the father, such as:
    • Affidavit found at the back of the Certificate of Live BIrth
    • Separate public document executed by the father
    • Private handwritten instrument made by the father expressly recognizing the child as his.
  • If the child’s birth has been registered already and the child has been assigned the mother’s last name, with or without father’s recognition, the father may execute an AUSF (Affidavit to Use the Surname of the Father).
  • IF the child was born outside the Philippines and the AUSF was executed in or outside the Philippines, the AUSF shall be registered at the Local Civil Registry Office in Manila.

What is the process involved in changing the child’s last name?

  • After registration of the public document or AUSF (whichever is applicable), the LCR of the city or municipality where the child was born shall annotate the record of birth.
  • The change/annotation shall also be written in the LCR’s registry book.
  • The recognition or acknowledgment made in a public document other than the record of birth or the AUSF shall be registered within 20 days from the date of execution.

If the child’s birth is not yet registered, can the child be assigned the surname of his or her father?

Yes. The father need only to execute the Affidavit of Admission of Paternity found on the second page of the Certificate of Live Birth (COLB). This should be filled out and signed by the father before submitting the document for registration at the LCR.

How to get an annotated copy of the child’s PSA birth certificate?

You may request for a copy of an annotated document that underwent RA 9255 at the PSA outlet in East Avenue, Quezon City. Make sure to get a confirmed appointment online before you visit. Bring the following as well:

  • Certified copy of the original Certificate of Live Birth (no annotation)
  • Copy of the annotated document
  • Certified copy of the public document and AUSF or private handwritten instrument and AUSF, together with the supporting documents and consent of the child, if the child is 18 years old or over.


Philippine Statistics Authority


Published by MasterCitizen

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One thought on “How Can An Illegitimate Child Use The Surname Of His or Her Father?

  1. Hi, good day po. What will be the process po para magamit ng mga anak ko un surname ng tatay nila. May naka attached po na acknowledgement letter nung tatay nila ang mga birth cert po. Pinoproblema po kasi ng anak kong panganay ung mga papers po nya s school di kasi narelease gawa dun sa birth cert nya n sa akin naka sunod..un po kasing school records nila since grade school ay naka sunod s tatay nila. Kaya nakatengga po un mga diploma anak ko s isang University. Di maka apply ng work kasi hinahanapan siya ng school credentials. Bale po ang panganay ko ay 23 yrs old at 19 napo ang bunso ko. Salamat po s kasagutan.  God bless po. 

    Sent from Yahoo Mail on Android

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