The goal of this presentation is the description of the epidemiologic evolution and changes in natural history of the human immunodeficiency virus infection (HIV) epidemic itself and its relation with the acquired immunodeficiency syndrome-related lymphoma (ARL). We have started with the description of the world's state of the HIV epidemic, its features since the first case report in the United States of America in 1981, through the peak of new diagnoses in 1993 until the event that changed the natural history of the disease: the era of the widespread use of the highly active antiretroviral therapy (HAART), introduced in 1995 in the world and in 1997 in our country. The widespread introduction of HAART led to dramatic reductions in AIDS related mortality and morbidity throughout the developed world with a marked fall in the incidence of the major opportunistic infections in AIDS. We describe the main risk factors for the development of ARL, and the prognostic factors for survival and response to treatment. There is no clear definition in the literature of the roll that has played the use of HAART in relation to survival and response to treatment in ARL, but there is evidence that the basal count of CD4 cells has increased with HAART, leading to a better survival and response in ARL. The debate regarding this issue is surely affected by factors such as degree of antiretroviral treatment compliance, antiretroviral therapy resistance and chemotherapy heterogeneity. Finally we present the preliminary results of the analysis of our experience in ARL from 1986 to 2003.