What is your passport number?

When the USCIS officer asks for the applicant's passport number, the applicant should respond by reading the number from the actual passport, which the applicant should have brought to the interview. Passport numbers vary by country in format. Most are 6 to 9 alphanumeric characters. The number is printed on the photograph page of the passport, near the top or bottom of the data section. The applicant should not need to memorize the number; the officer expects the applicant to look it up on the physical passport at the interview.

The passport-number question helps confirm several things at once. First, the passport number is part of the applicant's identity record. Second, providing the number allows the officer to cross-reference with the I-94 entry/exit records that USCIS and Customs and Border Protection maintain. Third, the question tests basic English ability to read numbers and letters aloud.

Applicants should practice reading their passport number aloud in advance. Numbers should be read individually (for example, "X 1 2 3 4 5 6 7 8" rather than "X one hundred twenty-three million..."). Letters should be pronounced clearly. Some passport numbers begin with a letter that designates the issuing authority or document type.

Applicants should bring all passports used during the residency period: the current passport, any prior passports that show travel during the past 5 years (or 3 years for spouses of U.S. citizens), and any expired passports with travel stamps relevant to physical presence calculations. Applicants who have passports from multiple countries (dual or multiple citizenship) should bring all passports and disclose all passport numbers. Applicants whose passport was lost or stolen and replaced should bring the replacement passport and any documentation of the loss. Applicants whose home country issued a special travel document instead of a regular passport (because of statelessness, refugee status, or other circumstances) should bring that document.

The N-400 application asks for passport information including issuing country, passport number, expiration date, and dates of issuance. The officer may verify that the application matches the actual passport. Applicants whose application has incorrect passport information (perhaps because the applicant got a new passport after filing) should bring the new passport and explain the change to the officer. The change is normal and easily corrected.

Applicants who do not have a passport at all (some stateless persons or certain other categories) should explain the situation. Honest disclosure with documentation is the right approach. The passport is one of the most important identification documents to bring to the interview.