Anomalous origin of the left anterior descending coronary artery from the right coronary artery can interfere with the location of the usual ventriculotomy during repair of tetralogy of Fallot. The purpose of this study was to compare the results of two operative techniques: (1) a 'tailored' right ventricular incision and outflow patch reconstruction and (2) placement of a conduit from the right ventricle to the main pulmonary artery. We reviewed the records of 416 patients who had complete repair of tetralogy of Fallot at the Mayo Clinic from 1973 through 1984. Twenty (5%) (median age 6.5 years) had anomalous origin of the left anterior descending coronary artery from the right coronary artery. Twelve of these patients had right ventricular outflow patch reconstruction, and eight had placement of a conduit from the right ventricle to the pulmonary artery. Three deaths occurred, all during hospitalization, two in the patch reconstruction group and one in the conduit group. The average reduction in right ventricular pressure postoperatively was slightly but not significantly greater than for the conduit group. These data indicate that correction of tetralogy of Fallot with anomalous origin of the left anterior descending coronary artery can be done with either patch reconstruction of conduit placement. Selection of the more appropriate procedure depends on the exact location and degree of tortuosity of the anomalous artery and the level and severity of right ventricular outflow obstruction.