Prominent apathy and/or irritability are frequently observed among individuals infected with the human immunodeficiency virus (HIV). Although these symptoms often occur as part of a mood disorder, compelling evidence suggests that they may occur independently of depression in neurologic disease/disorder. The current study examined the prevalence of both apathy and irritability among a sample of HIV-infected individuals and explored the degree to which these neuropsychiatric (NP) phenomena were associated with performance on neurocognitive measures thought to be sensitive to the potential CNS effects of HIV-1. Clinician-administered rating scales assessing apathy and irritability were administered to 65 HIV-seropositive (HIV+) and 21 HIV-seronegative (HIV−) participants who also completed a dual-task reaction time paradigm and the Stroop task. NP disturbance was significantly more prevalent among HIV+ participants compared with HIV− controls and was associated with specific neurocognitive deficits suggestive of executive dysfunction. Relative to both HIV− controls and to neuropsychiatrically intact HIV+ participants, those HIV+ individuals with evidence of prominent apathy and/or irritability showed deficits in dual-task, but not single-task, performance and on the interference condition of the Stroop. Unexpectedly, NP disturbance did not show a robust relationship with HIV disease stage. These results suggest that the presence of prominent apathy and/or irritability among HIV+ individuals may signify greater HIV-associated CNS involvement. In HIV/AIDS, the disruption of frontal–subcortical circuits may be a common mechanism causing both executive dysfunction and NP disturbance. (JINS, 2000, 6, 336–347.)