The effects of age, type of return, presence of pulmonary venous obstruction, obstruction to left heart filling, systemic arterial oxygen saturation (Ao O2%), pulmonary-to-systemic flow ratio (Qp/Qp), pulmonary-to-systemic resistance ratio (Rp/Rs%), and mean pulmonary artery-to-mean systemic arterial pressure ratio (MPAP/MSAP%) in 35 cases of total anomalous pulmonary venous return seen in the last 5 years, were studied in relation to prognosis and management. The surgical mortality was increased in patients with anomalous venous return to the right common cardinal system (right superior vena cava and azygos vein) regardless of age and was significantly lower in patients over 6 months of age and in those who had preoperative intensive medical management. No relation was found between surgical mortality and Ao O2%, Rp/Rs, MPAP/MSAP%, or the presence of pulmonary venous obstruction. The small size of the left atrium rather than the small size of the left ventricle is felt to be one of the reasons for operative failure. The importance of obstruction to left heart filling at the atrial level was stressed. Until technics for surgical treatment of this group of anomalies in early infancy become more successful, we recommend balloon atrial septostomy in combination with intensive medical management as effective palliative treatment for most of these patients in the first 6 months of life.