Family Based Preference Categories

Permanent Residence is based upon one’s relationship to a U.S Citizen or Permanent Residence is categorized pursuant to statute into various preferences.  
Immediate Relatives:  Spouses, Parents or Unmarried Children under age 21
First Preference:  Unmarried Sons and Daughters of US Citizens
Second Preference:  Spouses, Sons and Daughters of Lawful Permanent Residents
Third Preference:  Married Sons and Daughters of U.S. Citizens
Fourth Preference:  Brothers and Sisters of U.S. Citizens
 
With the exception of immediate relatives, there are numerical limitations placed on numbers of individuals who may immigrate each year to the United States.  In each of the above categories the application for classification of the relative as a resident is made on the appropriate CIS form, which is filed with the CIS Service Center having the proper jurisdiction over the case.
 
Documentation:
 
Documentation establishing the legal status of the petitioner and the relationship between the petitioner and the alien relative must be submitted with the application. This usually consists of a copy of the green card or naturalization certificate or birth certificate of the petitioning relative and copies of the birth records, marriage certificates or other relevant records.  The requirements vary for each type of relationship.

Note: Certain relationships do not qualify and a petition may not be filed.