To evaluate the efficacy of percutaneous transluminal angioplasty as a possible alternative to repeated open heart surgery for symptomatic aortocoronary saphenous vein graft stenoses, the procedure was initiated at Shadyside Hospital in January 1978. Percutaneous transluminal angioplasty has been used in nine aortocoronary graft stenoses and 11 native coronary artery stenoses. Of the nine grafts, eight (88 percent) were successfully dilated, including three that had been totally closed as visualized by angiography. Of the 11 coronary dilations, only four (36 percent) resulted in improved flow. The more favorable results experienced with the graft dilations was thought to be due to the nature of the occlusive processes affecting these grafts. The fibrous intimal proliferative disease that is found in most grafts is easily compressible, while the nature of the disease in the coronary arteries is not so readily predictable. Better instrumentation and careful evaluation before and after angioplasty will improve the results and extend the indications for coronary artery and saphenous vein graft transluminal angioplasty.