This report summarizes the results of neurologic and cerebrospinal fluid (CSF) study findings in over 400 of the 649 human immunodeficiency virus-infected US Air Force personnel, evaluated as of Dec 31, 1987. Eighty percent of these patients were entirely asymptomatic and immunologically normal, 13% had low T-helper lymphocyte counts and/or cutaneous anergy, and only 7% had opportunistic infection. Sixty-three percent of all patients had some CSF abnormality. Sixty percent of the asymptomatic group had at least one abnormal result, over 25% had three or four CSF abnormalities, and over 7% had five or six abnormal values. When patients with evidence of blood-brain barrier leak were excluded, significant differences were seen between disease groups with regard to CSF glucose, CSF IgG levels, and CSF IgG synthesis. No human immunodeficiency virus-related central nervous system abnormalities were found on neurologic examination in immunologically intact asymptomatic patients regardless of CSF findings. No clear-cut predictor of impending central nervous system complications has, as yet, been identified from the CSF parameters studied.