We report a rare case of cerebellar degeneration that was diagnosed at autopsy in a patient who developed lithium intoxication accompanied by neuroleptic malignant syndrome. This 63 year old female, who suffered from manic depressive psychosis, had received lithium bicarbonate at a daily dose of about 1000 mg for 4 years. She developed a high fever and extrapyramidal symptoms resembling a neuroleptic type of malignant syndrome and died 1 month later. Autopsy revealed an almost complete loss of Purkinje cells with a mild reduction of granule cells in most areas of the cerebellar hemisphere and vermis, except for the tonsil and flocculus, and mild gliosis in the dentate nucleus. In cases of suspected lithium intoxication, one must be alert to the possibility of neuroleptic malignant syndrome and to prevent cerebellar degeneration.