Acquired immune deficiency syndrome (AIDS) and related disorders are increasingly and unsettlingly prevalent. The authors describe neuropsychiatric, psychosocial, and ethical-legal problems associated with HIV infection that are commonly encountered in a consultation-liaison psychiatry setting. Because of H1V's potential for undermining cognitive function, they recommend a systematic neurobehavioral assessment for the differential diagnosis of emotional disturbance, including a test battery that also identifies neurotoxic effects of pharmacological agents. Among significant psychosocial and ethical-legal problems are patients' reactions to AIDS, their fears of social abandonment, staff burnout, antibody testing, confidentiality, and the use of life-support measures. The consultation-liaison psychiatrist's awareness of the complexities of HIV-related neuropsychiatric symptoms and psychosocial issues can be of enormous benefit to medical caregivers and to the patients themselves.