Recently, the arterial switch operation has received more interest and increased application for many patients with TGA [Transposition of the Great Arteries]. Not all patients, however, are suitable candidates for this approach, and its success will be measured against the Senning procedure. From June 1982 through June 1989, 48 consecutive patients underwent correction of TGA by a modification of the Senning procedure in our hospital. 34 were males and 14 females, with ages ranging from 3 months to 99 months [mean age 14 months]. The patients were divided into two groups, group I [TGA with intact ventricular septum or without significant pulmonary hypertension] and group II [TGA with significant pulmonary hypertension]. The hospital mortality was 9.5 % in group I and 55.6 % in group lI. 31 patients were discharged from the hospital after a Senning operation and have been followed a mean of 31.2 months. There were 5 late deaths, 3 in group I and 2 in group II. All patients were followed up with EKG, echocardiogram, and in several cases, Holter monitor and cardiac catheterization and angiography were also performed. There have been arrhythmias in 7, superior vena caval obstruction in 5, pulmonary venous obstruction in 2 and tricuspid insufficiency and/or right ventricular dysfunction in 16 patients. The Senning operation for Simple TGA can be performed with a low operative mortality and morbidity, but tricuspid insufficiency and/or depressed right ventricular function can be a problem with prolonged follow up.