The disappointing long-term results of the Fontan procedure led the authors to assess substitution with partial cavo-pulmonary connections for definitive palliative treatment of single ventricle malformations. One hundred and fifteen patients with a mean age of 4.3 +/- 4.5 years (1 month-22 years) were treated by termino-lateral anastomosis between the superior vena cava and corresponding pulmonary artery, either of necessity because of a contraindication to total cavo-pulmonary connections (31 cases) or electively (84 cases). Another source of pulmonary flow was preserved or added in 76% of children, the operative mortality was 4% and the secondary mortality 3.5%. Significant complications were observed in 15% of cases with a secondary morbidity of 13%. Reoperation was required in 18 cases (16%). In fact, the death rate was higher in indications of necessity (19 versus 3.6% in elective procedures). Similarly, the number of serious complications (veno-venous or pulmonary arterio-venous fistulae, ventricular dysfunction) was higher in this group than in patients undergoing an elective procedure (23 versus 2.4%). After 4.8 +/- 3.2 years' follow-up, 73% of children treated of necessity and 95% of children treated electively were well despite mild cyanosis (average saturation of 86 +/- 6%). On condition that these results are confirmed at long-term as present follow-up is relatively short, this strategy would seem to be justified, providing mild cyanosis with little functional impairment is accepted, so avoiding the serious complications of Fontan-like circulations.