The dynamics of the spread of the AIDS epidemic in Brazil have been studied by an analysis of cases reported between 1987 and 1995. The analysis evaluates characteristics of the epidemic as it changed over time, geographic region and special sub-populations affected. Data collected by the National Coordination of sexually-transmitted diseases (STD's) and AIDS of the Health Ministry were reviewed and incidence rates calculated. Three periods of time were identified (1987-89, 1990-92, and 1993-95) and the distribution of cases by ages group, sex, risk factor sub-population, and major geographic region recorded. Several observations can be made from this information: 1) The disease began among homosexual/bisexual males in larges metropolitan areas of the southeast of Brazil. 2) It spread to other risk groups such as intravenous drug users (IDU)and the recipients of blood productos. 3)The diseases increased rapidly between 1987-89, and 1990-92, but then showed a plateau, particularly in the homosexual/bisexual group.4) Increase in cases persisted in the IDU group. 5)The incidence among heterosexuals and in smaller municipalities has continued to increase indicative of a shift in the dynamics of the epidemic. The shift in the characteristics of the epidemic away from special groups and towards the socially vulnerable, poorly educated, heterosexual, smaller minicipalities require new preventive strategies adaptable to regional patterns of each social structure, economy and culture.