The clinical history of all 17 patients with anomalous left coronary artery presenting over the last 20 years was studied, with special emphasis on those who underwent reimplantation of the anomalous coronary artery into the aorta, a procedure that became our "treatment of choice" during this period. These patients were also evaluated for ventricular performance, residual mitral regurgitation, and wall integrity. Early in our experience with reimplantation, two patients died while we waited for them to achieve a more favorable size for surgery. Eight of nine survived reimplantation; three of these were under 1 year of age when operated upon. One of these eight patients has required additional mitral valvuloplasty, but all are doing well clinically up to 12 years after operation. Preoperative left ventricular ejection fraction of 0.37 +/- 0.16 increased to 0.67 +/- 0.07 (p less than 0.001) by 1 year after surgery, despite ventricular wall abnormalities in four patients. Thus reimplantation of the anomalous left coronary artery should be undertaken upon diagnosis, since surgery can be performed successfully in infancy, with resultant improvement in ventricular function and an adequate clinical condition for at least 12 years.