An 11 to 15 year follow up (mean 12.7 years) of 90 patients undergoing surgery for coarctation of the isthmus of the aorta is reported. There were 7 late deaths. Of the survivors 87% were normotensive (B.P. less than or equal to 160/100 mmHg) and 90% were asymptomatic and leading a normal life. Five cases-all with an aortic prosthesis-had to be reoperated for recurrent coarctation. These figures are comparable with those found in the literature. The best long-term results are obtained in patients who have the operation while young (less than 20 years), who have no associated abnormality, and whose coarctation can be treated by resection with direct anastamosis.