U.S. citizenship can only be obtained by birth or by the naturalization process. If you are trying to get American citizenship for your foreign spouse, naturalization is the only way. For your spouse to be eligible to apply for naturalization on the basis of being married to a U.S. citizen, your spouse must be at least 18 years old. It is also necessary for you to have been married to your spouse and have been living with your spouse in the U.S. during the past 3 years. If your foreign spouse meets these criteria, then your spouse can apply for a Permanent Resident Card (or Green Card) through marriage. Once your spouse has completed the Green Card process, she/he is eligible to begin the U.S. citizenship process.

When applying for naturalization on the basis based on being married to a U.S. citizen, you must submit the following documents:
A completed N-400 "Application for Naturalization" form.
A photocopy of both sides of your Permanent Resident Card.
Two identical color photographs. You must write your name and "A-number" lightly in pencil on the back of each picture. Please keep in mind that you are not permitted to wear eyeglasses or earrings in the photo.
A check or money order to cover both the application fee and the biometric fingerprinting services fee. Cash will not be accepted as payment.

Evidence that your spouse has been a U.S. citizen for the last three years. This evidence can take the form of a:
• Birth certificate (if your spouse never lost citizenship since birth), or

• Naturalization certificate, or

• Certificate of Citizenship, or

• The inside of the front cover and signature page of your spouse's current U.S. passport, or

• Form FS-240, "Report of Birth Abroad of a Citizen of the United States of America."

Your current marriage certificate.
If applicable, proof of termination of all prior marriages of your spouse. Divorce decree(s), annulment(s), or death certificate(s) are all accepted.

Documents that make reference to you and your spouse, such as:
• Tax returns, bank accounts, leases, mortgages, or birth certificates of children, or
• Internal Revenue Service (IRS)-certified copies of the income tax forms that you both filed for the past three years, or
• An IRS tax return transcript for the last three years.

After mailing your U.S. citizenship application with all required documents to the appropriate USCIS Lockbox Facility (the address varies based on the state you live in), the USCIS will tell you where you must go to be fingerprinted. You will then have to attend an interview, in which you will be asked questions about your U.S. citizenship application and background. It is wise to be clear and honest while answering the interviewer's questions. Your English reading, writing, and speaking skills will also be put to the test. Apart from the English proficiency exam, the INS officer will ask you civics questions on U.S. history. You are required to answer 6 out of 10 questions correctly to pass.

Based on your test results and interview, your U.S. citizenship application will be granted, continued, or denied. If you are unsuccessful because of the tests, you can reapply as soon as you feel you have sufficiently prepared to pass. In several other cases, you can reapply for naturalization as well, but you will have to start the entire naturalization process from scratch. If your application has been granted, on the other hand, the oath ceremony is the final part of the U.S. citizenship process. The USCIS will notify you of the ceremony date. An officer will read out the oath and you will be asked to repeat his words. A Certificate of Naturalization will be given to you as proof of your newly acquired American citizenship status. Once you have received your Certificate of Naturalization, you will be eligible to apply for a U.S. passport as well.