What is the difference between a Certificate of Citizenship and a Certificate of Naturalization?

A Certificate of Naturalization is issued to someone who became a citizen through the naturalization process — a green-card holder who filed Form N-400, passed the tests, and took the Oath of Allegiance. A Certificate of Citizenship is issued to someone who is already a citizen automatically, by acquisition at birth abroad to a U.S.-citizen parent or by derivation through a parent's naturalization before age 18, and who files Form N-600 to document that status. Both are valid proof of citizenship; the difference is the path each documents.

Which form do I file for a Certificate of Citizenship?

Form N-600, the Application for Certificate of Citizenship. It is filed by a person who already acquired or derived U.S. citizenship and needs official documentation of it. It is not the same as Form N-400, which is the application to become a citizen through naturalization. Filing N-400 when you are already a citizen means paying a higher fee and going through a process that does not apply to you.

Does a Certificate of Citizenship require the civics test and oath?

Generally, an N-600 applicant does not take the English or civics tests because the person is not naturalizing. However, USCIS generally administers the Oath of Allegiance before issuing a Certificate of Citizenship after Form N-600 approval, unless the oath is waived. USCIS generally waives the oath for children under 14 and may waive it if the person cannot understand its meaning.

What do "acquisition" and "derivation" mean?

They are the two ways a person becomes an automatic citizen eligible for a Certificate of Citizenship. Acquisition means a child born outside the United States to a U.S.-citizen parent acquires citizenship at birth, if statutory conditions are met. Derivation means a child becomes a citizen after birth, through a U.S.-citizen parent while the child is under 18, is a lawful permanent resident, and resides in the United States in that parent's legal and physical custody. Both make the person a citizen automatically, so they file N-600 to document status rather than N-400 to obtain it.

How do I replace a lost Certificate of Citizenship or Naturalization?

File Form N-565, the Application for Replacement Naturalization/Citizenship Document. The same form replaces either certificate if it is lost, stolen, or damaged. You do not refile the original N-600 or N-400 to get a replacement — those are the original application forms, while N-565 is specifically for replacing a document that was already issued.

Is one certificate better proof of citizenship than the other?

No. A Certificate of Citizenship and a Certificate of Naturalization are equally valid proof of U.S. citizenship for purposes such as applying for a passport, verifying employment eligibility, or claiming benefits. They simply document different paths to citizenship. A U.S. passport is also accepted as proof of citizenship in most everyday situations, though the certificate is the underlying documentary evidence of status.

Certificate of Citizenship vs Naturalization (N-600)

TL;DR

A Certificate of Citizenship and a Certificate of Naturalization are both official proof of U.S. citizenship, but they document two different paths to it, and knowing which is which is a common naturalization-exam point. A Certificate of Naturalization is issued to a foreign national who became a citizen through the naturalization process — someone who held a green card, filed Form N-400, passed the interview and tests, and took the Oath of Allegiance. It is issued at or just after the oath ceremony. A Certificate of Citizenship is issued to someone who is already a citizen automatically, without naturalizing — a person who acquired citizenship at birth abroad to a U.S.-citizen parent, or who derived it through a U.S.-citizen parent while under 18, as a lawful permanent resident residing in the United States in that parent's legal and physical custody. That person files Form N-600 to document citizenship they already hold; they do not take a test or naturalize because they are already a citizen by operation of law. The key contrasts: naturalization is a process you go through (N-400) and the certificate proves you completed it; a Certificate of Citizenship (N-600) only documents status that already exists. To replace either lost certificate, the form is N-565. Both certificates are equally valid proof of citizenship for a passport, employment, or benefits.

Two paths, two documents

The reason there are two certificates is that there are two fundamentally different ways a person can be a U.S. citizen other than by birth in the United States. One is to go through naturalization; the other is to already be a citizen automatically because of a parent. Each situation produces its own proof document.

A Certificate of Naturalization is the end product of the naturalization process. A lawful permanent resident (green-card holder) who meets the residence, physical-presence, good-moral-character, English, and civics requirements files Form N-400, attends an interview, passes the tests, and takes the Oath of Allegiance. Only after the oath does the person become a citizen, and the Certificate of Naturalization is the document proving it. For the process that leads to it, see our guide to the N-400 application walkthrough.

A Certificate of Citizenship documents citizenship that a person already holds without ever naturalizing. It is issued to people who became citizens automatically — either at birth abroad to a U.S.-citizen parent, or by derivation through a U.S.-citizen parent while the child is under 18, is a lawful permanent resident, and resides in the United States in that parent's legal and physical custody. Because these people are already citizens by law, the certificate does not make them citizens; it simply provides official evidence of a status that already exists.

Acquisition and derivation: who gets a Certificate of Citizenship

USCIS uses two terms to describe the automatic citizens who are eligible for a Certificate of Citizenship. Acquisition refers to a child born outside the United States to a U.S.-citizen parent, who acquires citizenship at birth if the statutory conditions are met. Derivation refers to a child who becomes a citizen after birth, typically when a lawful-permanent-resident child's parent naturalizes and the child is under 18 and residing with that parent.

Both routes are governed by the Immigration and Nationality Act, and the substantive rules for who qualifies are detailed and depend on the law in effect at the relevant time. This article is about the documentation — which certificate proves the status — not the eligibility rules themselves. For the substantive acquisition and derivation rules, see our guides to acquisition of citizenship by birth abroad and child citizenship acquisition. The point for this topic is that anyone in these categories is already a citizen, and the Certificate of Citizenship obtained via Form N-600 is how they prove it.

The forms: N-600, N-400, and N-565

Three form numbers commonly appear in this area, and mixing them up is a frequent and costly error:

Form	Purpose
N-400	Application for Naturalization — filed by a green-card holder who wants to become a citizen through the naturalization process
N-600	Application for Certificate of Citizenship — filed by someone who already acquired or derived citizenship and wants documentation of it
N-565	Application for Replacement Naturalization/Citizenship Document — filed to replace either certificate if it is lost, stolen, or damaged

The most common mistake is filing N-400 when N-600 is the right form. A person who is already a citizen through a parent does not need to naturalize — filing N-400 would mean paying a higher fee and going through a process, including tests and an oath, that does not apply to someone who is already a citizen. The right form is N-600, which asks USCIS to document the citizenship that already exists. There is no English or civics test for an N-600 applicant because the person is not naturalizing; they are asking USCIS to document citizenship they already hold. However, if USCIS approves Form N-600, USCIS generally administers the Oath of Allegiance before issuing the Certificate of Citizenship unless the oath requirement is waived, such as for a child under 14 or a person unable to understand its meaning.

What this looks like in practice

Consider two people. The first came to the United States as an adult on a green card, lived here for five years, applied with Form N-400, passed the interview and the English and civics tests, and took the Oath of Allegiance at a ceremony — that person receives a Certificate of Naturalization. The second was born abroad to a U.S.-citizen parent, or moved here as a child and became a citizen automatically when their parent naturalized before they turned 18 — that person is already a citizen and files Form N-600 to receive a Certificate of Citizenship.

For exam purposes, the trigger words matter: "naturalized," "N-400," "oath ceremony," and "former green-card holder" point to a Certificate of Naturalization; "acquired at birth abroad," "derived through a parent," "already a citizen," and "N-600" point to a Certificate of Citizenship. Both are equally valid proof of citizenship, and either can be replaced with Form N-565. A U.S. passport is also acceptable proof of citizenship in most everyday contexts.

Frequently Asked Questions

What is the difference between a Certificate of Citizenship and a Certificate of Naturalization?: A Certificate of Naturalization is issued to someone who became a citizen through the naturalization process — a green-card holder who filed Form N-400, passed the tests, and took the Oath of Allegiance. A Certificate of Citizenship is issued to someone who is already a citizen automatically, by acquisition at birth abroad to a U.S.-citizen parent or by derivation through a parent's naturalization before age 18, and who files Form N-600 to document that status. Both are valid proof of citizenship; the difference is the path each documents.
Which form do I file for a Certificate of Citizenship?: Form N-600, the Application for Certificate of Citizenship. It is filed by a person who already acquired or derived U.S. citizenship and needs official documentation of it. It is not the same as Form N-400, which is the application to become a citizen through naturalization. Filing N-400 when you are already a citizen means paying a higher fee and going through a process that does not apply to you.
Does a Certificate of Citizenship require the civics test and oath?: Generally, an N-600 applicant does not take the English or civics tests because the person is not naturalizing. However, USCIS generally administers the Oath of Allegiance before issuing a Certificate of Citizenship after Form N-600 approval, unless the oath is waived. USCIS generally waives the oath for children under 14 and may waive it if the person cannot understand its meaning.
What do "acquisition" and "derivation" mean?: They are the two ways a person becomes an automatic citizen eligible for a Certificate of Citizenship. Acquisition means a child born outside the United States to a U.S.-citizen parent acquires citizenship at birth, if statutory conditions are met. Derivation means a child becomes a citizen after birth, through a U.S.-citizen parent while the child is under 18, is a lawful permanent resident, and resides in the United States in that parent's legal and physical custody. Both make the person a citizen automatically, so they file N-600 to document status rather than N-400 to obtain it.
How do I replace a lost Certificate of Citizenship or Naturalization?: File Form N-565, the Application for Replacement Naturalization/Citizenship Document. The same form replaces either certificate if it is lost, stolen, or damaged. You do not refile the original N-600 or N-400 to get a replacement — those are the original application forms, while N-565 is specifically for replacing a document that was already issued.
Is one certificate better proof of citizenship than the other?: No. A Certificate of Citizenship and a Certificate of Naturalization are equally valid proof of U.S. citizenship for purposes such as applying for a passport, verifying employment eligibility, or claiming benefits. They simply document different paths to citizenship. A U.S. passport is also accepted as proof of citizenship in most everyday situations, though the certificate is the underlying documentary evidence of status.

Bottom Line

A Certificate of Naturalization and a Certificate of Citizenship are both proof of U.S. citizenship, but they document different paths. A Certificate of Naturalization goes to someone who became a citizen through the naturalization process — a green-card holder who filed Form N-400, passed the interview and tests, and took the Oath of Allegiance. A Certificate of Citizenship goes to someone already a citizen automatically, by acquisition at birth abroad to a U.S.-citizen parent or by derivation through a parent's naturalization before age 18; that person files Form N-600 to document existing status and does not take the English or civics tests; USCIS may still administer the Oath of Allegiance before issuing the certificate unless the oath is waived. To replace either certificate, the form is N-565. The exam trap is filing N-400 when you are already a citizen and only need N-600 to prove it. Both certificates are equally valid proof. For related topics, see our guides to the N-400 application walkthrough, acquisition of citizenship by birth abroad, and child citizenship acquisition.

Source: USCIS Policy Manual, Vol. 12 Part K Ch. 2 — Certificate of Citizenship · USCIS Form N-600, Application for Certificate of Citizenship · USCIS Form N-565, Replacement Naturalization/Citizenship Document