We followed prospectively all patients with HIV infection admitted to the infectious diseases ward at Auckland Hospital over a seven month period. Neurological manifestations of HIV infection were the primary reason for admission in 18 of the 55 patients (33%). Diagnoses were usually presumptive, based on history, clinical findings, radiological appearances and response to empirical therapy. Eight patients had cerebral toxoplasmosis, three primary cerebral lymphoma, two cytomegalovirus retinitis, two HIV neuropathy, one cryptococcal meningitis, one HIV encephalopathy, and one HIV meningitis. Another patient with HIV infection was admitted to the neurology ward at Auckland Hospital with HIV myelopathy during the same seven month period. The median survival of the patients treated for presumptive toxoplasmosis was 7.5 months. Only two patients had not developed AIDS, one having HIV meningitis and the other HIV myelopathy, and in both, symptoms resolved spontaneously with no relapse at one year follow up. The spectrum of neurological manifestations of HIV infection is wide. Investigations to determine the most likely diagnosis are indicated and specific therapy may lead to both excellent palliation and prolonged survival.