Coronary restenosis after balloon angioplasty is a slow process that develops over a few months. In some patients, with an initially successful angioplasty, an artery that originally had only moderate stenosis becomes totally occluded as a result of restenosis. This report describes 16 such patients out of 415 dilated lesions with late angiographic follow-up. Ten patients presented with stable angina pectoris, 5 had unstable angina and only one was admitted with a small myocardial infarction. Visible collaterals were present in 15 patients. Except for the patient who sustained myocardial infarction, none of the late angiograms showed the typical morphological features of acute lesion. We conclude that total coronary occlusion late after successful angioplasty of an artery that was moderately narrowed is rare. The 'restenotic' occlusion is a slow process that stimulates collateral formation and thus the risk of myocardial infarction is small.