We evaluated 54 patients with pulmonary atresia and ventricular septal defect who were referred during the first year of life between 1972 and 1992. Particular emphasis was given to the nature of the pulmonary blood supply and its influence on outcome. Ductal supply of confluent pulmonary arteries was present in 30 patients (55.6%, group I), whereas 24 patients (44.4%, group II) had a pulmonary blood supply that was entirely (31.4%) or predominantly (13.0%) dependent on systemic collateral arteries. Over the 20 years there was no significant difference in actuarial survival between the two groups. Corrective surgery was performed in 8 of 30 patients in group I (26.7%)-significantly more than in group II (4 of 24, 16.7%). Arborization abnormalities of the pulmonary arteries (stenosis of unbranched and intrapulmonary arteries) were almost exclusively present in patients with systemic collateral arteries (p < 0.03), accounting for the lower probability of undergoing corrective surgery in group II patients. During the first decade of this study (1973-1983) corrective surgery was attempted in 9.6% of patients, with 42% mortality; and during the second decade (1983-1993) surgery was performed in 39.1% of patients, with 26% mortality, a significantly lower figure. Improving surgical results, complete preoperative demarcation of the pulmonary blood supply, and a more aggressive approach with early unifocalization of the pulmonary blood supply may invalidate comparison with retrospective data on the advisability of attempting to correct this anomaly. The present paper provides data against which treatment of infants with pulmonary atresia and ventricular septal defect presenting during the next decade can be compared.