Ten cases of total abnormal pulmonary venous connection are described: 5 cases with supracardiac drainage, 4 with sub-diaphragmatic drainage and one with intracardiac drainage, 3 cases with supradiaphragmatic drainage, and 4 with subdiaphragmatic drainage have undergone surgical treatment. Some developmental, embryological and pathophysiological signs of this malformation are reported. The more significant clinical and instrumental data arising from our personal cases and from review data are discussed. In the clinical description a distinction is made between cases with venous obstruction and those without venous obstruction. The importance of hemodinamic tests, which allow us to identify the type of connection present, and whether or not there are associated malformations, are underlined. The natural history is conditioned by the presence of venous obstruction, by the value of the pulmonary hyper-flow and by the possibility of communication between the two circulatory districts. The prognosis of the cases with marked obstruction, and of those with irreversible cardiac failure is one of rapid deterioration: surgical correction in the first months of life is the only therapeutic possibility, even if the death risk is high. The cases without venous obstruction, and with fairly normal weight and circulation, are corrected surgically at a later age with much more favourable results.