To provide a better understanding of the etiology of subjective sleep complaints in HIV-infected individuals, a study to evaluate sleep/wake disturbances in 10 healthy HIV-infected male volunteers was performed. All subjects were HIV-infected but had no history of AIDS-related infections, and considered clinically asymptomatic. Interviews and sleep questionnaires revealed sleep complaints in nine subjects. Five healthy HIV-seronegative male subjects, with no history of sleep complaints, were also evaluated. Sleep architecture analyses detected that, in comparison to published normative data and to negative controls, there was a significant increase in the total percentage of slow wave sleep (SWS) and an increase in the percentage of SWS in the later sleep cycles. When compared with normative data, an increase in stage 1 shifts, rapid eye movement (REM) periods, and arousals were also observed in the HIV-infected group. Significant decreases in sleep latency, total percentage stage 2 sleep, and average REM durations were also observed in the HIV-infected group compared with normative data. These sleep architecture abnormalities could not be attributed to known sole primary sleep disorders, first night effect, medications, anxiety or depression. This study indicates that sleep disturbances occur early in the course of HIV infection and suggests that the observed alterations of sleep physiology may be a consequence of central nervous system involvement and/or immune defense mobilization in the early phases of HIV infection.