Magnetic resonance images of 37 patients with schizophrenia and 37 age- and sex-matched volunteers were acquired. The caudate nucleus and putamen were traced on axial slices from the most superior extent of the caudate to the most inferior point where the caudate and putamen merge. Two subtypes of schizophrenia were compared, the Kraepelinian subtype (n=13), characterized by an unremitting and severe course, and the non-Kraepelinian subtype (n=24), characterized by a remitting course and some periods of self-care. Patients with good outcome schizophrenia had larger relative mean putamen size (0.0129) than poor outcome patients (0.0123) or normal controls (0.0121), but not caudate size. This enlargement was most marked for the dorsal putamen and right hemisphere. Striatal size was not related to whether patients were currently being treated with atypical or typical neuroleptics or whether they had been predominantly treated with typical or atypical neuroleptics over the past 3 years. This suggests the possibility that the expansion of putamen size may be a physiological correlate of neuroleptic responsiveness or that small putamen size at disease onset may be a predictor of outcome.