The objective of the study was to describe the underlying causes of death of HIV-infected patients in the HAART era and to focus on those related to opportunistic infection (OI), in a national multicentre study ('Mortalité 2000'). A total of 964 deaths were recorded and 924 cases were available for analysis. Underlying cause of death were AIDS-related (47%), viral hepatitis (11%), non-AIDS cancers (11%), cardiovascular diseases (7%) and others (11%). Among patients who died of AIDS events, 262 (27%) died of at least one OI. OIs reported at the time of death were Cytomegalovirus infection 67 times, Pneumocystis jiroveci pneumonia 56, disseminated Mycobacterium avium intracellulare infection 53 and cerebral toxoplasmosis 48. Compared to patients who died of other causes, patients who died of OIs were younger and more likely to be infected through heterosexual contact, in poor socioeconomic conditions, migrants, more recently diagnosed for HIV infection, and naive of antiretroviral therapy and OI prophylaxis. OIs are still a major cause of death in HIV-infected patient in the HAART era, especially among patients recently diagnosed for HIV infection and who do not have access to care, as well as in long term infected patients where prophylaxis should be revisited.