Varicella-zoster virus (VZV) causes ocular and other central nervous system (CNS) disease in human immunodeficiency virus (HIV)-infected persons. To study the prevalence of CNS disease due to VZV, cerebrospinal fluid (CSF) specimens from 84 consecutive HIV-infected patients with new neurologic symptoms were tested for VZV DNA by a polymerase chain reaction (PCR) assay. Six patients were PCR-positive for VZV in CSF; 3 additional patients were subsequently identified who were not part of the serial population sample. Among these 9 patients, all had clinical presentations consistent with ocular and other CNS disease due to VZV; 4 were without zoster on presentation. Sustained improvement in association with antiviral therapy was observed in 3. Therefore, VZV DNA was detected in the CSF of 7% of HIV-infected patients presenting with neurologic symptoms; the diagnosis of VZV-related CNS disease was facilitated by this assay; improvement in association with antiviral therapy was observed in some patients.