The long-term results of praziquantel therapy in 141 patients with neurocysticercosis are presented. Seventy-five patients (53%) were considered to be cured because the cysts or nodules disappeared or became calcified following praziquantel treatment and the patients were asymptomatic at the end of a 5-year follow-up period. An additional 35 patients (24.8%) improved clinically and radiographically. The intraventricular Cysticercus cysts of five patients in this group were not affected by praziquantel and had to be surgically removed. The remaining 31 patients (21.9%) were unchanged or became worse probably because, prior to therapy, Cysticercus larvae had caused tissue damage. The fact that praziquantel did not affect intraventricular cysts suggests a low concentration of the drug in the cerebrospinal fluid. Surgery continues to be an important tool in the treatment of cysticercosis to remove parasites that do not respond to praziquantel therapy as well as for the relief of intracranial hypertension.