How to Register a U.S. Citizen Baby Born in Mexico

To register a U.S. citizen baby born in Mexico, file a Consular Report of Birth Abroad (Form FS-240) at a U.S. embassy or consulate in Mexico before the child turns 18, then use that document to obtain a U.S. passport and Social Security number. Separately, register the birth with Mexico’s Civil Registry to secure your child’s Mexican citizenship and birth certificate. Both citizenships can be held together, and Mexico fully recognizes dual nationality.

Confirm Your Child Qualifies for U.S. Citizenship

A baby born in Mexico doesn’t automatically become a U.S. citizen just because a parent is American. The citizen parent must meet a physical presence requirement under federal law, and the threshold depends on the parents’ situation.

If one parent is a U.S. citizen and the other is not, the American parent must have lived in the United States for at least five years total before the child’s birth, with at least two of those years after age 14. The five years don’t need to be consecutive. Time on active duty in the U.S. Armed Forces or working for the federal government abroad also counts.¹

If both parents are U.S. citizens, the bar drops sharply: at least one parent must have lived in the United States at some point before the birth, with no minimum duration.¹

Unmarried parents face an added wrinkle when the father is the U.S. citizen. Before the child turns 18, the father must establish a biological relationship by clear and convincing evidence (a DNA test satisfies this), agree in writing to support the child financially until age 18, and legally acknowledge paternity through a sworn statement, legitimation under local law, or a court order. Missing the 18th-birthday deadline forfeits the citizenship claim.² If the U.S. citizen mother is unmarried, the standard physical presence rules apply without these extra steps.

File the Consular Report of Birth Abroad

The Consular Report of Birth Abroad (CRBA, Form FS-240) is the State Department document proving your child acquired U.S. citizenship at birth. It functions like a federal birth certificate and is accepted as proof of citizenship for passports, Social Security, school enrollment, and every other federal purpose.³

You must file before the child turns 18. There’s no penalty for waiting, but without a CRBA your child can’t get a U.S. passport, a Social Security number, or otherwise use their citizenship. Most parents apply within the first few months.

Start the application online through the State Department’s MyTravelGov portal by creating an account and completing the eCRBA form. You can — and should — apply for your child’s first U.S. passport at the same appointment.³

Gather the Documents

Most of the work happens before your appointment. You’ll need:

The child’s Mexican birth certificate: a certified copy from Mexico’s Civil Registry (Registro Civil). The U.S. Embassy in Mexico generally accepts the Spanish version without a separate translation, though some consular posts request an informal one, so check with yours.
Proof of the U.S. citizen parent’s citizenship: a valid U.S. passport, naturalization certificate, or prior CRBA, plus government-issued photo ID.
Marriage certificate, if the parents are married. If either parent was married before, bring documentation showing how that marriage ended.
Evidence of physical presence in the U.S.: school transcripts, Social Security earnings statements, tax returns, employment records, utility bills, and lease agreements. You need enough to prove the required five years (or any period of residence, if both parents are citizens). This is the piece most parents scramble to assemble.

If the consular officer can’t confirm the biological relationship between the child and the citizen parent from the paperwork, the State Department may require DNA testing arranged through an approved lab. Outside tests aren’t accepted.⁴

Attend the Embassy Appointment

After you submit the eCRBA application and pay the $100 CRBA fee online, schedule an in-person appointment at the U.S. Embassy in Mexico City or one of the U.S. consulates around the country. Wait at least 72 hours after paying before booking so the payment can process.⁵

Both parents and the child must attend. A consular officer reviews your original documents, interviews you, and decides whether to approve the application. If you’re also applying for the child’s first U.S. passport at the same appointment, bring a completed Form DS-11 but don’t sign it until the officer asks.

If one parent can’t attend, the absent parent must submit a notarized DS-3053 Statement of Consent for the passport application. For unmarried parents where the U.S. citizen father is absent, he must also submit a notarized DS-5507 Affidavit of Parentage, Physical Presence and Support.

The CRBA fee is $100. A child’s passport book (under age 16) costs an additional $135.⁶ Processing after approval typically takes several weeks and varies by consulate.

Register the Birth With Mexico

Mexico’s constitution grants citizenship to every person born on Mexican territory, regardless of the parents’ nationality. Your child is a Mexican citizen from birth, with no residency requirement to meet.

Register the birth at the local Civil Registry (Registro Civil) in the municipality where the baby was born. The hospital usually provides a certificate of live birth, which you take to the registry to obtain the official Mexican birth certificate (acta de nacimiento). You’ll need that acta for the CRBA application as well.

Mexico fully recognizes dual nationality, so your child doesn’t have to choose between countries or renounce either citizenship. Mexico does treat your child as a Mexican national for all domestic legal purposes while in the country, which for male dual citizens can include military service registration requirements.⁷

Get Both Passports and Use Them at the Right Border

Your child needs two passports, and the country of entry dictates which one to present. Mexican law requires dual nationals to enter and leave Mexico using their Mexican passport. U.S. law requires all American citizens, including infants, to use a U.S. passport when entering the United States by air.⁷⁸

For a Mexican passport, both parents must appear in person at a Mexican government office (Secretaría de Relaciones Exteriores or a delegación). Bring the child’s Mexican birth certificate, proof of the child’s identity (a medical certificate with a photo works for infants), and parental identification. Both parents sign a consent form (OP-7).

For land or sea crossings from Mexico into the United States, children age 15 and under can enter with an original or copy of a U.S. birth certificate or CRBA instead of a passport. Air travel still requires a valid U.S. passport at every age.⁸

Apply for a Social Security Number

Once you have the CRBA and U.S. passport in hand, apply for a Social Security number. The Social Security Administration needs to see the CRBA or passport as proof of citizenship, so you can’t apply before those documents are issued.⁹

Some U.S. embassies and consulates in Mexico let you submit the SSN application at the same appointment as the CRBA, though it won’t be processed until the CRBA and passport are finalized. The embassy forwards the application to the Social Security Administration’s Federal Benefits Unit, and the whole process can take up to six months from abroad. Applying in person at a Social Security office inside the United States is much faster, typically under two weeks.

The SSN also matters at tax time. To claim the Child Tax Credit, your child must have a Social Security number valid for employment, issued before the due date of the return (including extensions) for the tax year you’re claiming.¹⁰

Plan for Ongoing U.S. Tax Filing

U.S. citizenship comes with a lifelong federal tax-reporting obligation. Every American citizen, wherever they live, must file a federal income tax return once their worldwide income exceeds the filing threshold. That applies to your child as soon as they have income, whether from a job, investments, or a Mexican bank account earning interest.¹¹

Families living in Mexico must report income from both countries to the IRS. Foreign tax credits and the foreign earned income exclusion usually prevent double taxation, but the filing requirement itself never disappears. Many dual citizens raised abroad don’t realize they’re required to file U.S. returns as adults, so it’s worth telling your child early.

1
Office of the Law Revision Counsel. 8 USC 1401 – Nationals and Citizens of United States at Birth
2
Office of the Law Revision Counsel. 8 USC 1409 – Children Born Out of Wedlock
3
U.S. Department of State. Birth of U.S. Citizens and Non-Citizen Nationals Abroad
4
U.S. Department of State. Information for Parents on U.S. Citizenship and DNA Testing
5
U.S. Embassy Mexico. Birth Abroad and Eligibility for U.S. Citizenship – CRBA
6
U.S. Department of State. Passport Fees
7
Secretaría de Relaciones Exteriores. Double Nationality
8
U.S. Customs and Border Protection. U.S. Citizens – Documents Needed to Enter the United States and/or to Travel Internationally
9
Social Security Administration. Learn What Documents You Will Need to Get a Social Security Card
10
Internal Revenue Service. Child Tax Credit
11
Internal Revenue Service. U.S. Citizens and Residents Abroad Filing Requirements