Between January 1981 and December 1983, 53 systemic-to-pulmonary artery shunts, Blalock-Taussig shunts (BTSs) and modified Blalock-Taussig shunts (MBTSs) were carried out either as a preliminary procedure before complete correction of heart defects or as a means of permanent palliation. Central shunts continue to pose early and late problems and we seldom use them. Fifteen patients underwent a BTS and 38 an MBTS with a 5 mm polytetrafluoro-ethylene (PTFE) graft. Their ages ranged from 3 days to 11 years; 21 patients were less than 3 months old and of these 15 had an MBTS; 36 patients were less than 1 year of age and 27 of them had an MBTS. Three patients were receiving prostaglandin at the time of surgery. The overall early hospital mortality was 5,6% (3 cases); these were babies less than 2 months old. The late mortality was 3,7% (2 cases); these deaths were not shunt-related and were in babies less than 4 months old. There were 4 cases of shunt failure (7,5%) at 6, 22, 26 and 27 months after operation; a second shunt was performed in all these patients. The 48 survivors have been followed up for an average of 23 months (range 5-41 months); 6 have already undergone a complete repair. Long-term results are difficult to assess accurately because of problems with follow-up. Eight of the 53 patients had mild congestive heart failure which responded to digitalis. Because of the reliability and excellent late patency of the PTFE prosthesis, we consider it to be superior to the Waterston shunt for relief of cyanosis in the neonate and infant and as reliable as the BTS.