A rare case of an infant with 'double inlet right ventricle' (straddling mitral valve) and double outlet right ventricle is described. Coarctation of the aorta was associated. A left to right shunt resulted from part of the mitral valve opening into the right ventricle and also from the presence of a ventricular septal defect. The infant's clinical features reflected the shunt, although the valvular abnormality had not been suspected clinically. It is anticipated that left atriography might have identified this rare type of straddling atrioventricular valve.