The types of cardiac and visceral anomalies of 146 autopsied cases of polysplenia are described. One hundred and five of these cases were from the literature and the other 41 cases were specimens we personally reviewed. The anomalies found support the previous description of this condition as bilateral leftsidedness. Each lung had 2 lobes in 55% of patients, and abdominal heterotaxia was present in 56%. Cardiac anomalies occurring in at least half of the patients include bilateral superior vena cava, interruption of the inferior vena cava with azygos continuation, ventricular septal defect, ostium primum defect, and morphologic left ventricular outflow obstruction. Not all patients with polysplenia have cardiac anomalies, and in many patients the cardiac anomalies are not complex. Fifty percent of the 146 patients died by 4 months of age and 75% before 5 years of age.