Thirty-six infants under one year of age underwent surgical repair of coarctation of the aorta between 1968 and 1983 in our institution. Coarctation was isolated or associated to a patent ductus arteriosus in sixteen cases, while in twenty it was associated with significant intracardiac disease. Twenty-nine patients were operated on in the first three months of life and in twenty a severe heart failure was present before the operation. Nine patients (25%) died while in the hospital: all of them were less than three months of age and all but one were affected by major intracardiac anomalies and severe heart failure. Surgical repair was by subclavian flap aortoplasty in twenty-nine cases, resection with end-to-end anastomosis in three, patch aortoplasty in three and Blalock-Park anastomosis in one. Operative mortality was unaffected by the surgical technique. The surviving children were followed-up for 30 +/- 7 months; one late death occurred suddenly, two months after the repair of a ventricular septal defect. An arm/leg pressure gradient, indicative of recoarctation, was detected in five cases: only one had been repaired by the subclavian flap technique, while the others were the only survivors of the end-to-end anastomosis and patch aortoplasty group. Subclavian flap aortoplasty is suggested as the operation of choice for coarctation of the aorta in the first year of life.