Since its original description,1 several histological examinations have shown that in Hallervorden-Spatz disease pathological amounts of iron are stored in the globus pallidus and reticular zone of the substantia nigra. This is also proved by the quantitative chemical findings recently obtained in our laboratory.2 In this connection two problems arise: (1) whether the local disturbance of iron metabolism in Hallervorden-Spatz disease can be demonstrated by in vivo examination, and (2) whether this disturbance in Hallervorden-Spatz disease is the result of disturbance of the general iron metabolism. To reach a conclusion in these problems, we have made a study of the iron metabolism with the help of γ-ray59Fe isotope in patients with Hallervorden-Spatz disease and in some other neuropsychiatric patients in order to make a comparison between the two groups. Material and Methods The material consists of 20 neuropsychiatric patients with the following diseases: schizophrenia, ten patients;