In 12 months since March, 1975, 25 of 27 patients with tetralogy of Fallot have had corrective operations without ventriculotomy. Infundibular obstructions were excised and ventricular septal defects were closed through a right artiotomy with retraction of the anterior leaflet of the tricuspid valve. Pulmonary valve stenosis was relieved through a pulmonary arteriotomy. In five patients the pulmonary annulus was patched 0.5 to 1.5 cm. into the right ventricle. Immediately after repair peak right ventricular-pulmonary arterial systolic pressure difference averaged 17 mm. Hg and ranged between zero and 40 mm. Hg. Cardiac indices averaged 2.85 L. per square meter per minute 4 hours after operation. All but two patients developed right bundle branch block. One patient with severe pulmonary hypertension died. Fourteen patients have been recatheterized. Right ventricular-pulmonary peak systolic pressure differences ranged between zero and 45 mm. Hg (mean, 22). Cineangiograms show contraction of the free right ventricular wall during systole. Transatrial repair of tetralogy of Fallot is feasible technically in many patients, avoids muscle necrosis and coronary arterial injury, and improves cardiac output in the immediate postoperative period.