The transposition of the great arteries (S,D,L) complex is delineated for the first time from the anatomic, diagnostic, and surgical standpoints in this study of 26 cases: 16 surgical and 10 postmortem, Transposition of the great arteries with situs solitus of the viscera and atria (S), D-loop ventricles (D), and L-transposition (L) was characterized by six additional interrelated anomalies that largely determined surgical management: (1) ventricular septal defect, usually conoventricular, in 96%; (2) malalignment of the conal septum, typically leftward and posteriorly, in 80%; (3) right ventricular hypoplasia in 50%; (4) pulmonary outflow tract stenosis in 27%; (5) ventricular malposition, such as superoinferior ventricles, in 23%; and (6) absent left coronary ostium resulting in ''single'' right coronary artery in 23%, Complete surgical repair was done in 81% of the surgical patients with a 12.5% hospital mortality rate and no late deaths, When there was no pulmonary outflow tract stenosis and intracardiac anatomy was uncomplicated, we undertook anatomic repair before 1 month of age, However, when pulmonary outflow tract stenosis coexisted, complete repair was deferred until after age 1 year, our currently preferred operation being the REV procedure (reparation a l'etage ventriculaire), When complex intracardiac anatomy precluded biventricular repair, a palliative procedure was performed in 19% without mortality, Hence, this experience indicates that surgical management of patients with the transposition of the great arteries (S,D,L) complex is feasible.