Coronary angiography has been used as a gold standard for assessing the results of such interventional procedures as balloon angioplasty, atherectomy and laser angioplasty. However, it is still imprecise in defining the extent and composition of atheromatous plaques, and can underestimate the severity of disease process in an eccentric lesion.1,2 The introduction of intravascular ultrasound as an imaging modality for atherosclerotic coronary artery disease has opened a new field for studying the morphologic changes before and after interventional procedures. Because of the incorporation of high-frequency transducers, it is possible to obtain images of the coronary arterial wall and assess the structural composition of the diseased segments.3-5 With the increasing number of procedures and devices being developed currently to deal with atherosclerotic obstruction, there is a need for a technique that will permit accurate assessment of alterations in the luminal area, integrity of the intimal surface, and the presence or absence of ulcerated plaques and thrombi. The present study describes our initial experience in using intravascular ultrasound to evaluate stenosed saphenous vein grafts undergoing angioplasty. © 1992.