56 male violent offenders and 20 male controls from the psychiatric personnel were studied by means of the glucose tolerance test. The results revealed some abnormal findings among those violent offenders who had an antisocial personality. Their blood glucose concentrations, having risen usually to a rather high level, fell to clinically significant hypoglycemia from which the return to the original basal values was slow. This abnormal glucose tolerance in the antisocial personality may have some connection with the etiology and poor prognosis of this disorder. The exact reason for these findings is not clear.