Chronic rejection, the most serious complication in long-term survivors of cardiac transplantation, was studied in 5 cardiac grafts obtained at retransplantation and in 15 post-mortem studies of patients who had survived 3 months to 10 years after transplantation. The usual clinical presentation was cardiac failure. Coronary angiography was performed in several cases and showed narrowing and non-opacification of small arteries often accompanied by thrombosis. Histology showed three types of vascular rejection: the most characteristic one, usually observed after the 6th month, was a stenosing fibrous endarteritis; another type of rejection, occurring earlier, was associated with acute myocardial rejection and presented as an inflammatory arteritis; the third type of vascular rejection was accompanied by widespread atheromatous lesions. The significance and pathogenesis of these lesions are discussed with respect to the clinical context with electron microscopic and immuno-histochemical data.