To analyse the epidemiological characteristics of AIDS cases diagnosed in the north-east of Brazil, since they were first recorded in the National Notifiable Diseases System - SINAN. To compare the number of registered AIDS cases in terms of the following characteristics: year of diagnosis (by decade), Federative Unit (FU) of residence, sex, self-declared gender, category of exposure to the virus, race and schooling; To discuss state and regional trends in AIDS cases; To outline the social and regional epidemiological profiles of AIDS; To assess the changes in the epidemiological pattern of the disease, decade by decade.