Two sisters with Hallervorden-Spatz syndrome (HSS) were treated with anti-Parkinson drugs. One showed the typical neuropathological lesions at death. The surviving sister has been treated with an iron-chelater without sustained effect, and with levodopa with improvement of motor abnormalities. Of 64 cases thought to represent HSS and studied post mortem, a group of 42 forms a distinct clinicopathologic entity. The remaining cases differ considerably from these, making their classification difficult at present. Hallervorden-Spatz syndrome may be the result of an inborn error of metabolism. Future studies of patients with HSS should include catecholamine analyses of cerebrospinal fluid and brain tissue and a search for viral infection, as iron studies have not been helpful.