Unmarried adult children and spouses of permanent residents are allowed to immigrate to the United States if their relationship to the permanent resident is established through a petition with Immigration and Naturalization Services. Unlike immediate relatives of U-S citizens, these family-based categories are allocated only a limited number of visas, so it may take several years before a visa is made available to a foreign relative. Spouses of permanent residents who have been married for less than two years can only obtain conditional permanent residence. In order for them to secure permanent status, they must petition the INS (I-N-S) to remove the conditional basis of their green card by the second anniversary of their admission date. If they have divorced the permanent resident spouse that sponsored them, they may still be able to have the conditional basis removed by filing a waiver of the joint petition requirement. Children of the beneficiary spouse, who are not also children of the petitioner, may immigrate with their foreign parent and be granted conditional green card status. While U-S citizens may sponsor their parents, as well as children and spouses, legal permanent residents are not eligible to sponsor their parents. Widows of permanent residents and orphans being adopted by permanent residents are likewise barred from admission. If your relative falls within one of these categories, it may be advisable for you to become a naturalized U-S citizen before sponsoring any foreign national relative. For more information on family-based permanent residence, consult an immigration attorney.