Objective: to study trends in mortality and survival in patients with AIDS attending an ID unit. Method: retrospective analysis of patients developing an AIDS-defining illness between April 1984, and November 1992. Survival was analysed by calculation of survival product-limit. Results: 71 patients were analysed (including four women), 23 of whom are still alive. Pneumocystis carinii pneumonia (PCP) was the most frequent AIDS-innex diagnosis: n = 36 (51%); 24 of these patients have died. HIV encephalopathy was the most frequent diagnosis at death; n = 16 (22.5%), followed by mycobacterial infection; n = 11 (15.5%), and PCP and CMV infection, each occurring in 10 (24%). One-, 2- and 3-year survival probabilities for patients with AIDS before 1987 were 0.46, 0.15 and 0 compared with probabilities of 0.63, 0.5 and 0.3 in those diagnosed after 1987; log rank -P <0.01. One- and 2-year survival probabilities in patients who received at least 3 months' zidovudine (AZT) therapy were 0.76 and 0.53 in those who are still alive compared with 0.55 and 0.33 in the deceased, while values for deceased AZT-naive patients were 0.29 and O.1; -P <0.O1, Thirteen (27%) deaths occured within 2 months of an AIDS-index disease. In 10 patients this was their first presentation to the department. PCP accounted for 8 (61%) of these deaths. Conclusions: survival in patients with AIDS has increased since 1987, when AZT was introduced. Early AIDS-related deaths are frequent in patients who have had no prior medical care. This has implications for education and provision of care in individuals with asymptomatic HIV infection.