Infection with HIV increases the risk of developing non-Hodgkin lymphoma and, to a lesser extent, Hodgkin disease. The introduction of highly active antiretroviral therapy (HAART) in 1996 changed the natural history of HIV disease, but the HIV-infected population also has changed in composition. Accordingly, the epidemiology of HIV-associated lymphomas now differs from that observed in the first 15 years of the HIV epidemic. In populations with access to HAART, reductions in lymphoma risk have been reported for NHL and suggested for Hodgkin disease, but long-term risks are as yet unknown. Lymphomas are increasingly common cancers in persons with HIV and are fatal in most patients, warranting continued attention to their incidence and etiology.