Seizure threshold (ST) is a parameter that differs in each person and can be modified both spontaneously and because of drug intake and/or other exogenous factors. A rise in ST during a course of electroconvulsive therapy (ECT) has been demonstrated in patients with depression and mania, but little information has been available as to whether the same result occurs in schizophrenia (SCZ). 11 male patients underwent estimation of the seizure threshold over a bilateral ECT course. Mean ST changed not significantly. No correlations were found between baseline ST and Positive and Negative Syndrome Scale (PANSS) scores. A significant positive correlation emerged between baseline ST and the variation of Hamilton Depression Rating Scale (HDRS) total and cognitive scores. The results suggest that ST in SCZ patients is not related to baseline psychopathological features, it is not related to clinical improvements of negative or positive SCZ symptoms and it does not change during the ECT course but it appears predictive of the improvement of affective and cognitive symptmos.