In contrast to Kawasaki syndrome the formation of coronary aneurysms caused by atherosclerosis has hardly been demonstrated. We report on a 56-year old patient, admitted to our hospital for cardiovascular evaluation before carotid surgery. He had no anginal pain, but a history of coronary artery disease with previous anterior myocardial infarction. Angiography revealed a collateralized LAD occlusion. Myocardial scintigraphy only demonstrated fixed perfusion defects. Surprisingly, MR imaging revealed large coronary aneurysms of the RCX and RCA. Angiographic follow up showed a rapid progression of ectatic towards aneurysmatic coronary lesions within 3 years. General pathophysiological mechanisms promoting ectatic coronary artery disease as a structural failure of the atherosclerotic remodelling process itself and chronic dilatatory stimuli due to endogenous and exogenous factors are discussed.