Thirty-one patients aged 60 years or more and infected with the human immunodeficiency virus type 1 (HIV-1) were followed up retrospectively and prospectively at the Regional University Hospital of Bordeaux. These patients represented 2.3 percent of all HIV infected patients followed up by the AIDS Clinical Epidemiology Group of Aquitaine. The male-to-female sex ratio was 1.4/1. Contamination resulted from blood transfusion in 58 percent of the cases. In 45.2 percent of these patients the belated diagnosis was revealed by a pathology pointing to AIDS. The most frequent clinical signs were candidiasis, herpes zoster or neurological manifestations which created a difficult differential diagnosis problem with senile dementia. The prognosis of the HIV infection was severe, with a 39.7 percent probability of survival at 18 months (confidence limits 95 percent: 18.6%, 60.8%). This prognosis could be improved by an earlier diagnosis and by a treatment suitable for elderly people.