This series of 5 cases with double outlet of morphologically left ventricular chamber includes 4 found during a review of 1700 heart specimens (incidence 0.23%) and 1 found at operation and successfully corrected. Abnormal atrioventricular connection precluding total correction was present in the 4 anatomical cases. Clinical diagnosis may be difficult and it is suggested that axial cineangiography may make anatomical diagnosis easier. Absence of the infundibular septum and aortic laevoposition are frequent. As some cases can be surgically corrected, accurate information is required on the size of the right ventricle, the morphology and function of the atrioventricular valves, the presence, size, and position of the ventricular septal defect, and the degree and type of outflow tract obstruction.