A long-term follow-up study was performed in 14 patients, operated for coarctation of the aorta in infancy. The median age at operation was 4 mth. Mean and median age at follow-up were 16 yr, and the follow-up time varied between 7 and 22 yr (mean and median 15 yr). At follow-up recoarctation was or had been present in 6 patients; there was no relation between the development of recoarctation and the age at operation. Concomitant aortic valve anomaly had been overlooked at the initial investigation in 3 patients. The systolic and diastolic blood pressure at follow-up was significantly elevated above the mean of normals; 2 of 8 patients without recoarctation clearly had diastolic hypertension. It seems as if even operation in infancy does not prevent hypertension later in childhood or adolescence in some of the patients, and it hardly seems justified to perform elective operations for coarctation of the aorta in infancy with the appreciable risk of recoarctation, until more long-term follow-up results are known. The patients should not be lost to follow-up.