Form N-600 guide: Application for Certificate of Citizenship

Wang Law Firm, LLC · David Wang, Managing Attorney · Attorney-reviewed · Updated October 2026

Form N-600's official title is Application for Certificate of Citizenship, and it is handled by U.S. Citizenship and Immigration Services (USCIS). Its purpose is to prove that you have already acquired U.S. citizenship by law, so that USCIS issues you a Certificate of Citizenship.

The essential difference between Form N-600 and the naturalization application, Form N-400, is that Form N-400 asks to "become" a citizen, while Form N-600 asks USCIS to confirm that you "already are" a citizen. It mainly applies to two groups: people born outside the U.S. to one or two U.S. citizen parents at the time of birth (acquisition at birth), and people who automatically became citizens by law before age 18, for example because a parent naturalized (derivation). Many people do not realize they may already be U.S. citizens and continue living as green card holders, or even plan to file Form N-400; that is exactly why Form N-600 should be assessed first.

At a glance

Who needs to file, and who does not

One point first: Form N-600 is not a required step for obtaining citizenship. A person who meets the legal requirements is already a citizen once those requirements are met; Form N-600 only provides a document issued by USCIS as proof. A valid U.S. passport also proves citizenship. Many families simply apply for a U.S. passport for their child and file Form N-600 later, when they need long-term proof that does not expire.

Situations where Form N-600 may apply:

• You were born outside the U.S., your father or mother was a U.S. citizen at the time of your birth, and that parent met the legally required U.S. residence or physical presence conditions;
• You lived in the U.S. as a green card holder, and before you turned 18 your father or mother naturalized as a U.S. citizen, and you lived with and were in the custody of that citizen parent;
• You were adopted by a U.S. citizen and acquired citizenship under the rules for adopted children;
• You derived citizenship long ago but never had any proof of it, and now need it for a passport, government benefits, petitioning for relatives and so on.

Situations where it does not apply:

• You never obtained a green card before turning 18, or you were already 18 when your citizen parent naturalized: you cannot derive citizenship under INA 320 and generally must file Form N-400 yourself once you qualify;
• A citizen's child who usually lives outside the U.S. and wants to obtain citizenship through an application before 18: generally uses Form N-600K (under INA 322), not Form N-600;
• You already have proof of citizenship that was lost or needs correcting: use Form N-565.

Legal basis and eligibility requirements

Citizenship is acquired under the law in effect when the relevant conditions were met. U.S. nationality law has been amended many times, so the requirements differ depending on the year of birth. Below we cover only the most common current situations; people born earlier (especially those born before November 14, 1986, or who were already 18 on February 27, 2001) are governed by different, older law and need a case-by-case analysis. USCIS's standards are in Volume 12, Part H of the Policy Manual.

1. Citizenship at birth: INA 301 and INA 309

This applies to people born outside the U.S. when at least one parent was a U.S. citizen. For example, for a child born after November 14, 1986, to parents who were married at the time of birth:

Notes:

• The "5 years, 2 of them after age 14" rule in INA 301(g) is a physical presence requirement counted in days; travel, study abroad and work trips all affect the calculation. Certain periods the parent spent abroad serving the U.S. government or armed forces, and periods spent abroad as the unmarried dependent child living with such a person, may count by law.
• The citizen parent must be the child's legal parent at the time of birth. For children born through assisted reproductive technology (ART), USCIS policy since 2021 is that a child is considered born in wedlock if the legal parents were married to each other at the time of birth and at least one legal parent has a genetic or gestational relationship with the child (that relationship does not have to be with the U.S. citizen parent). For these cases, check current official rules.
• Born to unmarried parents (INA 309): a citizen father must establish the blood relationship by clear and convincing evidence; he must have been a U.S. citizen at the child's birth; he (if living) must have agreed in writing to provide financial support until the child turns 18; and before the child turns 18 the child must have been legitimated, the father must have formally acknowledged paternity, or paternity must have been established by a court. The father must also meet the physical presence requirement. For a citizen mother, the requirement depends on the child's date of birth: for children born on or after June 12, 2017, the same 5-year / 2-year requirement as 301(g) generally applies; for children born before that date, a requirement of 1 year of continuous physical presence applies.

2. Automatic citizenship before 18: INA 320 (Child Citizenship Act of 2000)

This applies to people who met the conditions on or after February 27, 2001, and were under 18 on that date. When all of the following are met at the same time at some point before age 18, the child automatically becomes a U.S. citizen, with no oath and no application required:

1. At least one parent is a U.S. citizen (by birth or naturalization);
2. The child is under 18;
3. The child is a U.S. lawful permanent resident (holds a green card);
4. The child resides in the U.S. in the legal custody and physical custody of that U.S. citizen parent.

Key points:

• The order in which the conditions are met does not matter, as long as they are all met on the same day before age 18. The most common situation: the whole family holds green cards, and one parent naturalizes while the child is under 18 and living with that parent.
• The green card is essential. A child living in the U.S. in student, work or other nonimmigrant status does not automatically become a citizen when a parent naturalizes.
• If the parents are divorced, "legal custody" is generally determined by the most recent court custody order; if the court ordered joint custody, the citizen parent does not need to be the sole custodian. A private agreement between the parents generally cannot change a court's custody arrangement.
• Stepchildren do not qualify (unless formally adopted and meeting the adoption requirements). Adopted children must meet the adoption provisions of INA 101(b)(1); for some adopted children who enter on IR-3 or IH-3 visas, USCIS issues a Certificate of Citizenship automatically, with no Form N-600 needed.
• The Citizenship for Children of Military Members and Civil Servants Act, effective March 2020, amended INA 320: children living abroad with a U.S. armed forces member (accompanying under official orders) or a U.S. government employee may also be treated as "residing in the U.S."; the other requirements must still be met.

3. Derivation under prior law (former INA 321)

People who were already 18 on February 27, 2001, are not covered by INA 320 and instead fall under the older law in effect at the time (former INA 321 and related provisions). The older law is usually stricter; for example, if the parents were not divorced, it generally required both parents to naturalize. These cases need a date-by-date analysis.

Tips for each part of the form

Form N-600 is roughly structured as: the basis of your eligibility, information about you, information about your parents, marital history, U.S. military service, and signatures. Follow the part numbering in the current edition.

• Eligibility basis: choose the basis on which you claim citizenship, such as "born abroad to U.S. citizen parent(s)," "derived after a parent naturalized," or "adoption." Choosing the wrong basis can send the review in the wrong direction.
• Information about you: your A-Number (if any), the date and manner of your entry to the U.S., and the date you obtained your green card. The green card date is critical in INA 320 cases and must match your green card.
• Information about your parents: how and when your citizen parent became a citizen (by birth, or by naturalization, with the certificate number), and your parents' marital status and marriage date. In INA 301 cases, list in detail the citizen parent's periods of physical presence in the U.S. before your birth; this is the core of the review.
• Custody and living together: in INA 320 cases, explain during what period the child lived with the citizen parent; if the parents divorced, explain the custody arrangement.
• Both parents' information: even if you claim citizenship through only one parent, you usually need to provide information about the other parent as well.
• Signature: sign as the instructions require; if the applicant is under 14, a parent or legal guardian may sign on the applicant's behalf.

Common mistakes: giving the parent's green card date as the naturalization date; ignoring the parent's periods abroad before the child's birth and overstating physical presence; failing to explain custody after the parents' divorce; and names that do not match the translation of the birth certificate.

Evidence and supporting documents

• Your birth certificate (the full version listing your parents' names), with an English translation if it is not in English;
• Proof of the citizen parent's citizenship: U.S. birth certificate, U.S. passport, Certificate of Naturalization or Certificate of Citizenship;
• Your parents' marriage certificate, and proof that any prior marriages of either parent ended (divorce decrees, death certificates);
• INA 301 / 309 cases: evidence of the citizen parent's physical presence in the U.S. before your birth, such as school transcripts, employment records, tax records, Social Security earnings records, leases, passport entry and exit stamps, and military service records. Witness affidavits alone are usually not enough;
• INA 320 cases: your green card; evidence of living with the citizen parent (school records, medical records, tax records showing the same address, etc.); if your parents divorced, the court custody order;
• Born to unmarried parents: legitimation or paternity documents, the father's written agreement to provide support, and so on; DNA testing may be needed in some cases;
• Adoption: the full adoption decree or adoption certificate;
• Proof of any name change;
• Documents not in English need a complete English translation and a translator's certification; see Translation requirements for immigration applications. For applicants born in mainland China, for example, make sure the birth medical certificate, household registration (hukou) records and notarial birth certificate are consistent with each other.

The focus of the evidence is to prove that "every condition for acquiring citizenship has been met." The burden of proof is on the applicant, generally by a "preponderance of the evidence."

How to file and fees

You can file Form N-600 online through a USCIS online account or mail a paper form to the address listed on the official page. This page does not list specific amounts; for the current filing fee, the fee exemption for current or former military members filing for themselves, and fee waiver (I-912) eligibility, see the USCIS fee schedule G-1055 and the official N-600 page, or read How to check U.S. immigration fees and processing times.

What happens after you file

1. Receipt notice: confirms your case has been accepted.
2. Biometrics: if USCIS requires it, go as scheduled to have your fingerprints and photo taken.
3. Request for evidence (RFE): if the evidence is insufficient, you will receive an RFE; the most common requests are for more evidence of the citizen parent's physical presence or of custody. See What to do when you receive an RFE.
4. Interview: USCIS may schedule an interview, or may approve without one if the evidence is sufficient. Bring all originals to the interview; applicants under 18 are usually accompanied by the citizen parent.
5. Approval and oath: once Form N-600 is approved, applicants age 14 or older generally must take an oath before receiving the certificate; applicants under 14 usually do not. Follow the USCIS notice.

For processing times, check the official USCIS processing times; for case status, see How to check your USCIS case status.

Common reasons for denial, and options after a denial

• The citizen parent's physical presence in the U.S. before the child's birth was insufficient or could not be proven;
• In INA 320 cases, the child was already 18 when the parent naturalized, or had not obtained a green card before 18;
• Living with, or being in the legal custody of, the citizen parent could not be shown (for example, the parents divorced and custody was with the noncitizen parent);
• For a child born to unmarried parents, legitimation or establishment of paternity was not completed within the required time;
• The wrong version of the law or the wrong eligibility basis was applied.

Options after a denial: after a Form N-600 denial, you can generally appeal to the USCIS Administrative Appeals Office (AAO) or file a motion to reopen / reconsider on Form I-290B, within the deadline stated in the denial notice. Note: Form N-336 does not apply to N-600 denials (N-336 is only for denied N-400 naturalization applications). If you have new evidence, you can also file a new Form N-600. If you truly do not qualify, you can assess whether to naturalize through Form N-400.

Form N-600 compared with similar forms and documents

Frequently asked questions

Official sources

• USCIS: Form N-600, Application for Certificate of Citizenship
• USCIS Policy Manual, Volume 12, Part H: Children of U.S. Citizens
• Policy Manual: U.S. citizens at birth (INA 301 and 309)
• Policy Manual: automatic acquisition of citizenship before age 18 (INA 320)
• USCIS fee schedule G-1055

Related reading

• Form N-400 guide: Application for Naturalization
• From green card to citizen: N-400 requirements and process
• Form N-565: replacing a Certificate of Naturalization or Citizenship
• Family-based immigration guide

This article is general information and is not legal advice. Laws and policies can change; rely on the latest official information and on an attorney's advice for your specific situation.