Congenital corrected transposition of the great arteries (C-TGA) is frequently associated with VSD and PS. Systemic atrioventricular valve regurgitation is also sometimes present in patients with C-TGA. It is though that left-sided A-V valve regurgitation is caused by the deformities of the tricuspid valve (TV) or intolerance of TV and the right ventricle (RV) against systemic pressure load. We had a patient with C-TGA associated with Ebstein's malformation. The patient suffered from congestive heart failure due to left-sided A-V valve regurgitation. In this case, the septal and posterior leaflets were displaced below the atrioventricular annulus. The edges of all valves were thickened and partially calcified. Focal agenesis was found in the septal leaflet. There was a distinct atrialized ventricle which had a thin wall and no trabeculae. It shaped like a diverticulum of 3 cm in depth toward the diaphragm. Preoperative cardiac catheterization showed that the functional RV had an adequate size (RVEDVI 162% of normal) and ejection fraction was 53%. Left-sided valve replacement was performed using SJM 31M with preservation of TV. Left-sided atrioventricular annulus was so deformed due to the diverticulum that the prosthetic valve was sutured at the ventricular wall below the atrioventricular annulus to which TV had attached. Good clinical result was obtained after surgical treatment.