Neurobehavioral functioning was tested in 34 asymptomatic HIV-seropositive and 43 HIV-seronegative male homosexual subjects without substance abuse and CNS disorders. The HIV-positive subjects exhibited mild motor slowing compared to the seronegative subjects. These differences remained after controlling for potential cofactors. Early neurobehavioral impairment in HIV infection seems limited to subclinical motor deficits and attributable to HIV rather than possible confounding factors.