Because of the possibility of surgical treatment of double inlet left ventricle, its basic morphologic features of surgical and imaging importance are analyzed. Seventeen hearts were studied with the segmental sequential system. The situs was solitus in thirteen; dextroisomerism in three and levoisomerism in one. The atrioventricular valves were separated in nine; there was a common atrioventricular valve in eight; straddling of the atrioventricular valve in seven and stenosis in two. The rudimentary right ventricle was to the right side in twelve hearts and to the left side in five. The discordant ventriculoarterial connection was the most frequent (seven), followed by the concordant one (five) and double outlet right ventricle (five). There was pulmonary stenosis in five. The ventricular septum did not reach the crux cordis. The ventricular septal defect was bigger in straddling atrioventricular valves than in valves completely open into the left ventricle, being restrictive in ventriculoarterial concordance. Surgical treatment varies as the complexity of this cardiopathy does, from cardiac septation to palliation procedures. The morphologic knowledge of this cardiac malformation is basic to interpret correctly the diagnostic imaging.