In order to examine right ventricular diastolic function after complete correction of pulmonary atresia with intact ventricular septum and critical pulmonary valvar stenosis, we undertook a prospective analysis of seven patients who had previously undergone successful repair. Comparison was with age and sex-matched controls. The relationship between antegrade pulmonary arterial diastolic flow and other indices of right ventricular dysfunction were compared. The ratio of the velocity of early rapid filling to that of atrial systolic flow was no different from normal, but the deceleration of early rapid filling showed significant shortening with inspiration in patients, but not in control subjects. All patients, but none of the controls, demonstrated significant antegrade diastolic pulmonary arterial flow during late diastole. Despite “normal” ratios ofvelocity of early rapid filling to systolic atrial flow, patients after complete correction of pulmonary atresia with intact ventricular septum and critical pulmonary stenosis have abnormal right ventricular diastolic function typical of a restrictive physiology. This presumably reflects incomplete adaptation due to the presence of endomyocardial fibrosis.