Summary:Of 431 consecutive patients who underwent coronary arteriography during the twelve month period ending December 1976, 23 (5%) had angiographically documented coronary artery ectasia. Of these only five had “pure” or isolated ectasia, whilst 18 had ectatic disease combined with coronary artery stenoses.Clinical findings that are significantly associated with ectasia are male predominance (96%), abnormal lipid patterns (64%), a positive family history of coronary artery disease (57%) and previous hypertension (50%). Anatomically, ectasia most often involved the right coronary artery (96%), then the circumflex artery (75%) and the left anterior descending artery (57%).Only seven (five with severe proximal stenoses) of the 28 patients had coronary artery bypass grafts. Care should be taken not to overdiagnose narrow segments between ectatic, dilated segments as being obstructions. Failure to appreciate this resulted in two patients with isolated coronary artery ectasia having bypass grafts performed with little relief of their sympt