

Most Immigrants with permanent residency get their green cards through the sponsorship of relatives. Two steps are involved. First, a U.S. citizen or permanent resident files a petition for his or her relative. If the petition is approved, the relative has a "basis to immigrate," or a path to a green card. Second, the relative for whom the petition is approved applies for a green card - from overseas, he or she applies at an embassy (called "consular processing"), or, from inside the U.S., he or she applies with the INS (called "adjustment of status").
There are two kinds of Petitions for relatives - "immediate relative" petitions and "family preference" petitions. The most obvious difference between these categories is timing - people for whom an immediate relative petition is approved can apply for a green card immediately, whereas people for whom a family preference petition is approved usually have to wait, usually at least a year or two, and in some cases ten years or more, until they can apply for a green card. (There are other important differences as well.) Note, however, that although "immediate relatives" can apply "immediately" for a green card, in reality it can take time, up to a year or more, to go through the immigration process.
Immediate Relatives are spouses and certain relatives of U.S. citizens. The relations that fit into this category include, citizens' children (so long as they are unmarried and under 21 years of age) and parents (so long as the citizen is 21 or older). These relationships include step-parents and step-children of citizens (so long as the marriage that created the step-relationship took place before the child's 18th birthday), and they include adoptive children and parents (so long as the adoption took place before the child's 16th birthday).
Again, people for whom immediate relative petitions have been approved can apply immediately for permanent residence.
