OBJECTIVE To describe changes in the coronary artery following heart transplantation (HTx) in patients who survived for 1 year or more. METHODS Yearly ventriculography and coronary angiography were performed in 171 out of 172 patients aged over 12 years who survived HTx in Norway for 1 year or more after the first operation in 1983. Mean follow-up was 5.2 years +/- 2.8, range 1-12. RESULTS Altogether 31 patients died in the follow-up period, 8 (26%) of them from coronary artery disease (CAD). Angiographic changes included coronary artery stenoses, diffuse changes with ectatic and narrowed segments of the major coronary vessels, peripheral changes with occlusions and tapering of the small vessels, and reduction in the left ventricular ejection fraction (EF). Significant stenosis developed in 43 patients and 19 of these developed an occlusion of one of the major coronary artery branches. The coronary arteries were without significant stenosis in 97% of the surviving 141 patients at 1 year after HTx and in 82% at 5 years. Completely normal findings were seen in 81% after 1 year and in 44% after 5 years. Progression to significant stenosis and occlusion was rapid once changes first appeared. CONCLUSIONS CAD contributed to a significant number of deaths. The stenoses could develop at any time after transplantation and usually progressed rapidly once the first changes appeared.