A selected population of 41 homosexual/bisexual asymptomatic HIV-positive subjects were administered neurophysiological tests to assess language, memory, attention, logic faculties and visuo-motor functions. HIV-positive subjects differed from individually matched control subjects only in certain measures of verbal memory. Longitudinal evaluation performed after 1.5 years, however, did not indicate any further development of this mild amnesic deficit. Despite the small number studied in our sample, there seems to be a trend for older subjects to be at greater risk of developing AIDS and cognitive abnormalities than younger subjects, while differences in immunological status play a significant role in disease progression.