A 25-year-old man died 10 years after a Dacron patch was used to repair a coarctation of the aorta. Death was due to rupture of an unrecognized aneurysm at the site of the patch. After the initial operation at the age of 15 years, there had been no signs of residual or recurrent obstruction. He had no evidence of hypertension and was discharged some years later from regular hospital follow-up to the care of his general practitioner. We strongly recommend that patients who have undergone repair of aortic coarctation by patch aortoplasty should have lifelong follow-up in cardiac units with imaging facilities for monitoring aortic dilation. We would now recommend surgical intervention in the presence of progressive aortic dilation.