There are five categories of immigrant visas that allow relatives of United States citizens and lawful permanent residents to become U.S. permanent residents. Because Congress has limited the number of people, by country, who can immigrate each year, for many categories and nationalities, there is a waiting list for the visa that can last from one to many years.

Eligible family members obtain "green cards," and the right to live and work indefinitely in the United States, as long as they do not commit any offense or take other actions that would render them deportable.

The five categories are the following:

• Immediate Relatives of U.S. Citizens - Spouses, Parents (where U.S. citizen child is 21 years of age or older) and Unmarried Children Under Age 21
   
  There is no wait list for a visa in this category.
   
  
• First Preference - Unmarried Sons and Daughters (21 years of age or older) of U.S. citizens
   
  There is a wait list for a visa in this category.
   
  
• Second Preference - Spouses and Unmarried Sons, Daughters, and Children of U.S. Lawful Permanent Residents
   
  There is a significant wait list for a visa in this category. Spouses and unmarried children (under the age of 21) of lawful permanent residents face a shorter wait than unmarried sons and daughters (21 years old or older).
   
  
• Third Preference - Married Sons and Daughters (age 21 or older) of U.S. citizens
   
  There is a significant wait list for a visa in this category.
   
  
• Fourth Preference - Brothers and Sisters of U.S. Citizens (U.S. citizen must be age 21 or older)
   
  There is a significant wait list for a visa in this category.
   
  

Persons immigrating based on a family relationship must be sponsored by their U.S. citizen or lawful permanent resident relative. However, special provisions may apply in the cases of spouses or children of U.S. citizens or lawful permanent residents who are physically or emotionally abused, which allow an individual to sponsor himself/herself.

Generally, the process of obtaining lawful permanent residency is divided into two stages. In the first stage, the U.S. citizen or lawful permanent resident relative files a "visa petition" with BCIS to demonstrate that his/her relative meets the criteria of one of the categories above. When BCIS approves the petition, and there is a visa available, the individual may proceed with the second stage of the process, the green card application. However, individuals who are classified as "immediate relatives" may proceed with both steps simultaneously.

Green card applications can be made to the BCIS if the individual is in the U.S. and is otherwise eligible, through the "adjustment of status" process, or through a U.S. Consulate abroad.