American citizenship must be obtained after an individual has obtained permanent residence (Green Card) after 5 years if the residence was on a work visa or after 3 years if the residence was obtained through marriage with an American citizen.

Eligibility requirements
Have resided in the United States as a permanent resident for at least 180 days per year.
Not have a criminal record for the crime of moral turpitude or other crimes that could result in more than one year’s imprisonment.
If the applicant for citizenship is paying child support, the applicant must demonstrate that the support has been paid regularly and that he or she is up to date with his or her payments.

Period of validity
For life.

Status of dependents
The spouse of the American citizen must apply for naturalization.
Children of permanent residents will be included in their parents’ citizenship application.