Infection with the human immunodeficiency virus (HIV-1) results not only in immunologic dysfunction but also in neurological and neuropsychological illness. Ten percent of all patients with the acquired immunodeficiency syndrome (AIDS) have a neurological complaint as their first sign of illness, 37% of AIDS patients have significant neurological dysfunction during their lifetime and 75% have neuropathological abnormalities on autopsy. Neuropsychological abnormalities have been reported in 8% to 67% of patients with AIDS and in 10% to 40% of people with HIV-1 infection. Neurological illness arises not only as a result of opportunistic processes but also as a result of primary HIV-1 infection of the nervous system. Thus, the large number of people infected with HIV-1 are also at risk of developing neurological or neuropsychological illness, even in the absence of immunological dysfunction or systemic illness. Since the first reports of HIV-1-related neurological illness in 1983, research into the neurological and neuropsychological complications of AIDS and HIV-1 infection has provided a number of new insights into the mechanisms and clinical manifestations of HIV-1 infection of the nervous system. The goal of Neurological and Neuropsychological Aspects of HIV Infection, a satellite meeting of the Vth World Conference on AIDS, is to bring together the world's experts in various aspects of HIV infection and its neurological and neuropsychological complications. These experts will first provide an overview course on the neurological complications of AIDS and HIV Infection. This course will be followed by a meeting during which several plenary talks will review the most important recent results of research in this area. Finally, during open scientific sessions, researchers from around the world will be able to share the results of their research in this field and have a forum for the discussion of this research. This international scientific meeting should result in an increased awareness of the neurological and neuropsychological aspects of AIDS and HIV infection; this increased awareness should result in improved care of patients with HIV infection as well as directing and coordinating future research into this critical area.