Establishing Paternity in Peru Outside Marriage: The Judicial Process and DNA Testing

What is the judicial process for establishing paternity outside marriage

When a child is born outside marriage and the father does not voluntarily acknowledge him or her (for example, by registering the acknowledgment with RENIEC), the mother, the child (once an adult), or anyone with a legitimate interest can go to a local justice-of-the-peace court and ask a judge to formally declare paternity. This mechanism is governed by Ley N° 28457, a law designed to be much faster and simpler than an ordinary paternity lawsuit, relying on biological DNA testing as the central piece of evidence.

How the process starts

Whoever has a legitimate interest files a request with the justice-of-the-peace court asking for a paternity declaration. The court then notifies the alleged father, who has a short deadline, counted from that notification, to formally oppose the future declaration if he disagrees. If he does not oppose within the deadline, the judge can declare paternity directly, with no further proceedings needed.

The DNA test: who pays, and what happens if there is no cooperation

When the alleged father does oppose, the court schedules a single hearing at which the biological DNA test is ordered. The cost of the test must, in principle, be paid by the respondent (the alleged father) directly at the hearing. If he does not pay, the process can be postponed for an additional short period; and if payment still does not happen, the judge can declare paternity as a consequence of that lack of cooperation, even without an actual DNA result. In practice, this functions as a strong disincentive against refusing or delaying the test.

If the test result is positive (a match), the opposition is rejected and paternity is established. If it is negative, the opposition is upheld and no filiation is established, with the costs of the process typically falling on whoever filed the claim.

Appeal

Whichever party disagrees with the outcome — whether the paternity declaration itself, the ruling upholding the opposition, or the child-support decision issued within the same process — can appeal to the specialized family court within a short deadline from being notified. The higher court must schedule a hearing and issue its ruling within similarly short deadlines, reinforcing the fast-track nature of the whole process.

What this page does NOT cover

This judicial process is different from the voluntary acknowledgment of a child born outside marriage before RENIEC (an administrative procedure with no judge involved), and it is also different from inheritance topics such as forced heirship. If, along with paternity, you also need child support to be set, see how child and family support is requested in Peru, and if the child lives with one parent, it is also worth reviewing child custody and visitation rights in Peru.

Important caveat

This page summarizes the general mechanism of Ley N° 28457 based on secondary sources that quote the statutory text, since we were unable to verify the exact current text directly against an official source (SPIJ, El Peruano, or the Poder Judicial itself) at the time of writing. Before filing or responding to a claim under this law, check the updated text in Peru’s official legal database (SPIJ) or consult a family lawyer, especially regarding the exact computation of the deadlines.

Did you know there’s a voluntary route before going to court?

Before starting a judicial paternity process, check whether the other parent would be willing to do a voluntary acknowledgment at RENIEC, which is faster and doesn’t require a lawyer or a judge.