Taeniosis and cysticercosis, diseases caused by the parasitic tapeworm Taenia solium, are distributed worldwide where pigs are eaten and sanitation is poor, and also in the more developed countries as a result of increasing migration. Neurocysticercosis is the commonest parasitic disease of the human nervous system. Immunological assays detect positivity for human cysticercosis in 8-12% of people in some endemic regions, which indicates the presence of antibodies against the parasite but not necessarily active or central-nervous-system infection. The only reliable tool for diagnosis of neurocysticercosis is imaging by CT or MRI. The presence of viable cysts with a mural nodule, associated with degenerative cysts and calcifications, is typical. Classification of neurocysticercosis into active, transitional, and inactive forms gives a good clinical-imaging correlation and facilitates medical and surgical treatment. The main clinical manifestations of neurocysticercosis are seizures, headache, and focal neurological deficits, and it can have such sequelae as epilepsy, hydrocephalus, and dementia. Treatment should be individually fitted for each patient, with antiepileptic drugs, analgesics, corticosteroids, or a combination of these. Anthelmintic drugs (praziquantel and albendazole) are used routinely, but so far no controlled clinical trial has established specific indications or definitive doses of treatment. Parenchymal forms of neurocysticercosis have a good prognosis in terms of clinical remission. The most effective approach to taeniosis and cysticercosis is prevention, which should be a primary public-health focus for less developed countries.