There are five major categories for Family Based Immigrant Visas. With the exception of the Immediate Relative category, there are limits on the number of visas that may be issued in each category each year. Each month the State Department published a Visa Bulletin, which states whether visas are available (current) in each respective category. You can determine whether a visa is available based on your priority date. In the family category, the priority date is the date your Petition for Alien Relative is filed with the INS. Immigration based upon one's relationship to a U.S. citizen or Permanent Resident is categorized as follows:     Immediate Relatives:     Spouses, Parents or Unmarried Children under age 21 of US Citizens     First Preference:    Unmarried Sons and Daughters of US Citizens     Second Preference:    A. Spouses and Minor Children of Permanent Residents      B. Unmarried Sons and Daughters of Permanent Residents     Third Preference:    Married Sons and Daughters of U.S. Citizens     Fourth Preference:    Brothers and Sisters of Adult U.S. Citizens With the exception of the Immediate Relative category there are numerical limitations placed on the numbers of individuals who may immigrate each year to the United States. Documentation : You must establish the appropriate relationship between the petitioner and the beneficiary. If the petitioner is a US citizen then he or she must submit a copy of his/her birth certificate if born in the US or naturalization certificate of naturalized. If the petitioner is a permanent resident then he must submit a copy of his/her alien registration card. The following are the additional documents, which must be submitted to sponsor the particular beneficiary: Husband or Wife: A certified copy of the marriage certificate and proof of the legal dissolution of all previous marriages of both parties. Parent: The petitioner (son or daughter) must submit a certified copy of his or her birth certificate showing the parent's names and the marriage certificate of the parents. Note- the petitioning son or daughter must be over age 21 to sponsor a parent Child: A certified copy of the child's birth certificate showing the names of both the mother and father and the marriage certificate of the parents. Brothers and Sisters: Certified copies of the birth certificates of both the petitioner and the beneficiary and the parent's marriage certificate. A petitioner may not file for a person if any of the below apply: An adoptive parent or adaptive child if the United States citizen gained permanent residence through adoption. A natural parent if the United States citizen child gained permanent residence through adoption. A husband or wife, if you were not both physically present at the marriage ceremony and the marriage was not consummated. A husband or wife if you gained lawful permanent resident status by virtue of a prior marriage to a US citizen or lawful permanent resident unless a period of five years has elapsed since you became a permanent resident or you can establish by clear and convincing evidence that the prior marriage was not entered into for immigration purposes or your prior marriage was terminated by the death of your former spouse. A grandparent, grandchild, nephew, niece, uncle, aunt, cousin or in-law.