The diversity immigrant visa category was established by the U.S. Department of State in to allow for immigration from countries that traditionally do not send many immigrants to the U.S. Diversity visas are awarded based on a lottery system, and so this category does not involve the priority dates and lengthy wait times that are part of most of the other immigrant visa categories. There are 55,000 diversity visas available per year and priority is given to countries that have traditionally low rates of immigration to the U.S.
In order to qualify for a diversity visa, you must have at least the equivalent of a high school education or at least two years of training or work experience within the past five years in an occupation requiring at least two years of training or experience. The program occurs annually within a specific time frame.