Permanent resident aliens may become naturalized U.S. citizens after meeting certain requirements set forth in the immigration laws. Permanent residents are not required to become citizens of the U.S. Many permanent residents do not seek U.S. citizenship because they would have to forfeit their citizenship in their native countries. 

Requirements to Becoming a Naturalized Citizen

In order to be eligible for citizenship in the United States, aliens must meet the following requirements:

1. Lawful admission as a permanent resident
2. Continuous residence (not to be confused with physical presence) in the U.S. for at least five years immediately preceding filing for naturalization (three years for the spouses of citizens)
3. Residence for at least three months immediately preceding the filing for naturalization in the state in which the petition is filed
4. Physical presence within the U.S. for an aggregate total of at least one half of the period of required continuous residence (two and a half years for most aliens, one and a half years for spouses of citizens)
5. Ability to read, write, and speak ordinary English
6. Knowledge and understanding of the fundamentals of the history and government of the U.S.
7. Good moral character and attachment to the principles of the U.S. Constitution
8. Continuous residence (again, not equated with physical presence) in the U.S. from the date of filing the naturalization application until actual admission to citizenship
9. Attainment of 18 years of age at the time of filing for naturalization (with certain exceptions for the children of other aliens who can be naturalized with their parents)