Treadmill exercise electrocardiography (TE) was recorded in 50 patients to evaluate the incidence of exercise‐induced ventricular arrhythmias (VAs) in a group of patients who underwent corrective surgery of tetralogy of Fallot (TF) more than four years previously. The results of rhythm evaluation were correlated with cardiac catheterization data as well as clinical information such as the age at surgery and the interval from surgery. Of the 50 patients tested, ventricular premature contraction (VPC) was confirmed in 12 patients (24%) on TE, while five patients (10%) demonstrated VPC on the standard ECG. The interval from surgery was significantly longer in those patients with VA (Group 1) than those without VA (Group 11) on TE (p<0.05). There was no significant difference of the age at corrective surgery between the two groups. In group I, the preoperative hemoglobin level was higher (p<0.05) and the right ventricular ejection fraction was lower (p<0.01). Exercise‐induced VAs are closely related to the length of period after surgery and the depressed right ventricular funct