Form N-600 vs N-400: Which Citizenship Form Fits Your Situation?

Written and reviewed by the N400Test.com team against official USCIS sources · Last reviewed April 2026 · Educational information, not legal advice.

Understand the difference between applying for naturalization with N-400 and applying for a Certificate of Citizenship with N-600. This guide explains the issue in plain language and points you back to official USCIS materials for current rules.

The Main Difference

Form N-400 is for eligible permanent residents applying to become U.S. citizens through naturalization. Form N-600 is for people seeking a Certificate of Citizenship based on already having a citizenship claim.

When N-400 Is Usually Reviewed

N-400 is generally reviewed when a lawful permanent resident wants USCIS to decide a naturalization application after meeting eligibility requirements.

When N-600 Is Usually Reviewed

N-600 is generally reviewed when someone may already be a U.S. citizen through a parent and needs USCIS documentation of that citizenship.

When to Get Guidance

If you are unsure whether you are already a citizen or need to naturalize, consider speaking with an immigration attorney or accredited representative before filing the wrong form.

Frequently Asked Questions

Is Form N-600 the same as Form N-400? No. N-400 is for naturalization. N-600 is for a Certificate of Citizenship when someone may already have a citizenship claim.

What if I am not sure whether I am already a citizen? Review USCIS guidance and consider qualified help before filing because the correct form depends on your facts.

Official USCIS Sources

This article is for educational purposes and is based on USCIS materials available when last reviewed. Always check USCIS.gov for the current version of forms, fees, and policy.