How long do I have to be married to a U.S. citizen to get U.S. citizenship?

First, let’s get one important thing straight: Marriage to a U.S. citizen makes you eligible for a green card. Having a green card for a certain number of years can make you eligible for U.S. citizenship. But it’s a two-step process -- at a minimum. In other words, even if your U.S. citizen husband sponsors you, you cannot go directly to becoming a U.S. citizen.

Below are the steps you will probably have to go through, and the typical amount of time that each one takes. (A note to anyone who isn’t in the exact same situation: Procedures differ for applicants who are outside the U.S., or who are inside the U.S. but not in lawful immigration status.)

• Your husband prepares a visa petition for you on Form I-130 issued by U.S. Citizenship and Immigration Services (USCIS) and you prepare an adjustment of status application (with Form I-485 and accompanying forms and documents) and you mail this package to USCIS.
• Several months later, USCIS calls you and your husband in for an interview. You are (if all goes well) approved for lawful conditional resident status – not permanent resident status, because you presumably will not have been married for a full two years by the time your interview date arrives.
• You are a conditional resident for two years. Ninety days before those two years are up, you and your husband submit a joint petition on Form I-751, asking that the conditions on your residence be lifted, thus allowing you permanent residence. Several months later, USCIS approves your request.
• If you remain married to and living with your U.S. husband for three years from the date of your approval for conditional residence, you can apply for U.S. citizenship (naturalization). If the marriage breaks up or you stop living together, you must count a full five years from the date of your approval for residence to apply to naturalize.

For comprehensive information on the application process, see Fiance and Marriage Visas: A Couple’s Guide to U.S. Immigration. Or, if you have any questions about complicating factors in your case, or wish help with the application process, consult an immigration attorney.