The late outcome in 160 patients aged 1 to 54 years who had surgical repair of coarctation of the aorta was examined 10 to 28 years postoperatively. Twenty years postoperatively the probability of survival of patients discharged from the hospital aged 1 to 19 years at operation was a little less than that of the general population (95% versus 97%). The discrepancy between patients and the general population was more marked in those aged 20 to 39 years and was grossly different when surgical repair was undertaken beyond age 40. There were 19 late deaths (12%), 79% due to cardiovascular disease. Thirteen patients had a poor result because of recoarctation (11 patients) or the development of complications at the site of repair (2 patients). Most patients were hypertensive before operation. The frequency of hypertension decreased markedly in the first few postoperative years. Blood pressure was normal in most patients 5 to 10 years after operation, but when followed up for longer periods the proportion of patients with hypertension increased. Hypertension was more common in patients operated on after 20 years of age than in those aged 5 to 19 years at operation (p = 0.007). The likelihood of being alive without complications and with a normal blood pressure was 69% at 10 years, 55% at 15 years, and 20% at 25 years postoperatively.