The following provides a list of the requirements for naturalization as laid out by the Immigration and Nationality Act and the Code of Federal Regulations, along with a detailed discussion of each requirement:

1.Technical Requirements
In general, an alien must be inlegal permanent resident status to be eligible to become a naturalized citizen of the U.S.  He must also be 18 years of age or older at the time of filing for naturalization. This applies when the alien is filing alone. Certain exceptions apply allowing a minor alien to become naturalized prior to the minor alien's 18th birthday.
 
2.Residential Requirements
An alien must reside in the United States for a continuous period prior to the filing of the naturalization application. If an alien is not married to an American citizen, he/she must reside in the U.S. for a continuous period of five years after lawful admission to the U.S. as a permanent resident. If an alien is married to a U.S. citizen, he/she must reside in the U.S. for a continuous period of three years following lawful admission to the U.S. as a permanent resident. The alien must be in marital union with the spouse citizen for three years before the alien's citizen exam date, and the citizen spouse must have been a citizen during that time. Immigration regulations define "marital union" as residing together.

A prolonged absence from the U.S. will break the continuity of the alien's residence in the U.S. for naturalization purposes, although it may not affect the alien's ability to return to the U.S. as a permanent resident.  The following lists three durations of absence from the US, and how absences of each length affect the continuity of residence requirement:

1.Absences from the US for 6 months or less: An absence from the U.S. of less than six months does not break the alien's continuity of residence in the U.S. for naturalization purposes.

2.Absences from the US for more than 6 months to less than 1 year:  If the break is for more than 6 months to less than one year, there is a rebuttable presumption of a disruption to continuity of residence.  This means that an absence of this length is normally considered to be a disruption to continuity of residence, but the following factors can be used to rebut this presumption and establish continuity of residence:
a.not terminating employment in the US;

b.presence of immediate family in the US;
c.retention of full access to a US home; and
d.not obtaining employment abroad

3.Absences from the US for one year or more: Generally, an absence of one year or more “shall” disrupt continuity of residence. If the break is over a year, an alien's continuity of residence can be preserved, and the break can be excused, if steps are taken prior to the expiration of a year abroad to preserve the residence and certain qualifications are met.
 
An alien applying for naturalization must have physically resided in the U.S. for one half the period required for continuity of residence. For aliens who are married to a U.S. citizen, the alien must have been physically present in the United States accumulatively for eighteen months within three years prior to the date of filing the application. For aliens not married to a U.S. citizen, the alien must have been physically present in the United States accumulatively for thirty months within five years prior to the date of filing the naturalization application. This requirement is cumulative but not continuous. An alien can leave and come back to the United States within the three or five years as much as he wants as long as he does not break continuity of residence, and as long as his total time spent in the United States adds up to eighteen or thirty months.

Residence is required for three months immediately preceding the filing of the naturalization application in the state in which the petition is filed. This requirement is met simultaneously with the continuous residency requirement. Continuous residence in the U.S. is also required from the date of filing until actual admission to citizenship.

3.Language Requirement
The prospective citizen must have an ability to read, write, and speak ordinary English. This is determined via testing by an immigration examiner. The portion of the English language requirement dealing with understanding and the ability to speak the language is determined by the alien's responses to questions asked by the immigration officer in the alien's interview. The alien's reading and writing proficiency is tested by written examination. The language requirement does not apply to:

1.Those who are physically unable to comply due to disability
2.Those who are unable to comply due to mental impairment
3.Those who are at least 50 years old at the time of filing and lived in the U.S. as a permanent resident for at least 20 years.
4.Those who are at least 55 years old and lived in the U.S. as a permanent resident for at least 15 years.

4.Knowledge and Understanding of the Fundamentals of U.S. History and Government Requirement:
The prospective citizen must have knowledge and understanding of the fundamentals of U.S. history and government. This is determined by the administration of a multiple choice test. In general, those exempt from the English requirement must still meet this requirement. Exceptions are those who are mentally and physically impaired and special considerations can be given to those who are exempt from the English requirement based on age and length of stay. Those special considerations are usually a test in modified form.
 
5.Good Moral Character and Attachment to the Principles of the U.S. Constitution Requirement:
The prospective citizen must have good moral character and attachment to the principles of the U.S. Constitution.  The alien might fail to demonstrate good moral character due to the following:

1.Involvement in prostitution, alien smuggling, and most criminal activity, particularly those that involve imprisonment for six months or more
2.Aliens who have committed adultery in a notorious and open manner as in a case where the adultery has led to the destruction of the marriage
3.Failure to properly comply with IRS laws regarding taxes
4.Failure to register with the Selective Service when the alien is required to do so.
5.Aliens who have committed and have been convicted of one or more crimes involving moral turpitude
6.Aliens who have committed and have been convicted of 2 or more offenses for which the total sentence imposed was 5 years or more
7.Aliens who have committed and have been convicted of any controlled substance law, except for a single offense of simple possession of 30 grams or less of marijuana
8.Aliens who have been confined to a penal institution during the statutory period, as a result of a conviction, for an aggregate period of 180 days or more
9.Aliens who have committed and have been convicted of two or more gambling offenses
10.Aliens who have earned his or her principal income from illegal gambling
11.Aliens who have been habitual drunkards
12.Aliens who have practiced polygamy
13.Aliens who have willfully failed or refused to support dependents
14.Aliens who have voted unlawfully in the US or made false claims to US citizenship
15.Aliens who have given false testimony, under oath, in order to receive a benefit under the Immigration and Nationality Act.