The "trilogy," consisting of pulmonary stenosis with intact ventricular septum, right ventricular hypertrophy, and a defect in the atrial septum, was first described by Fallot.1 In his series of seven patients, the stenosis was valvular in six and infundibular in one. All seven had a patent foramen ovale, and in one a second defect of the atrial septum was present. Although the trilogy of Fallot is considered to be an infrequent lesion, growing experience with surgery for congenital heart disease has shown it to be commoner than previously thought. Abrahams and Wood2 in their series found tetralogy of Fallot in 14% and trilogy in 1.2%. In this institution, a total of 370 cases of congenital heart disease have come to surgery. Of this group, 22 were patients with trilogy—an incidence of 6%. This report details our experience since 1951 with the surgical treatment of these 22 cases