Cerebellar structures were measured in 30 chronic schizophrenic men and 18 healthy men using high resolution MRI. The volume of the posterior superior vermis was found to be significantly smaller in the schizophrenic men, but there was no difference in other cerebellar regions or the intracranial volume. The findings support the view that within the cerebellum the posterior superior vermis may be selectively reduced in men with chronic schizophrenia.