Twenty-five patients with diagnosis of total anomalous pulmonary venous connection, who had undergone corrective surgery, were studied at variable time period after surgery with 24-hour ambulatory electrocardiographic monitoring (Holter) and echocardiography. The aim of this study was to record arrhythmias, if any, and to correlate occurrence of arrhythmia with adequacy of repair and other related variables. All the patients were clinically asymptomatic. Twenty-four hours ambulatory electrocardiographic monitoring of these patients showed the presence of significant arrhythmias in 21 of the 25 patients. These included supraventricular ectopics in 19 patients, ventricular ectopics in 8, atrioventricular block in 2, right bundle branch block and atrial fibrillation 1 each and atrial tachycardia in 2 patients. There was no correlation between development of arrhythmia and age at repair, type of connection, operative approach and adequacy of repair. The study indicates that cardiac arrhythmias can occur in otherwise asymptomatic patients after correction for total anomalous pulmonary venous connection. Thus, these patients require long-term follow-up, even if they are asymptomatic.