We report analysis of surgical results in 110 consecutive infants and children who underwent atrial repair of simple complete transposition using the Senning operation between February 1978 and May 1990. Mean age at operation was 5.4 months ± 6.1 (range 1 week to 4 years); 75 were less than 6 months old. There were 72 males and 38 females. Operative mortality rate was 5.5%, with one late death. Average follow-up is 48.1 months with 44 followed greater than 3 years, and 27 greater than 5 years. Postoperative cardiac catheterization was performed in 48 patients. Right ventricular ejection fraction averaged 0.52 ± 0.08 and was normal in 28 patients. Response of right ventricular ejection fraction to afrerload stress was abnormal in 12 of 14 patients tested. Right ventricular ejection fraction increased normally during exercise in 6 patients, but was abnormal in 15. Mild tricuspid regurgitation was noted in 12 patients. Mild obstruction of the superior caval vein was noted in 4 patients. Baffle leak requiring reoperation occurred in one patient. Fifty-seven of 90 patients are in sinus rhythm by latest electrocardiogram. Postoperative electrophysiologic studies were performed in 34 patients, and Holter monitoring in 25. Significant arrhythmia occurred in 26 patients: 6 patients required pacemakers for slow junctional rhythm or complete heart block; 20 additional patients have a junctional rhythm. Six patients have delayed sinus nodal recovery time. At last follow-up, 88 children (98%) are in New York Heart Association functional Class I, and 2 (2%) are in Class II. The Senning operation for compete transposition can be accomplished with a low operative and late mortality. Serious baffle complications requiring reoperation are rare. Surviving patients are clinically well, but arrhythmias and depressed right ventricular function may limit their long-term functional status.