Heart transplantation has become an accepted and successful treatment for end-stage heart disease with survival rates of 80-90% after one year and 70% after 5 years. During the early posttransplant period (6-12 months), patients are subject to two major complications: rejection and infection. Fortunately, a certain degree of graft tolerance develops, allowing the immunosuppressive therapy to be progressively tapered off with a concomitant decrease in infectious problems. Long-term survival, however, is largely dependent on the development of an accelerated atherosclerosis in the graft, which is believed to represent some kind of chronic rejection. This transplant vasculopathy is documented by means of coronary angiography with an incidence of approximately 5 to 10% per year. It is not surprising therefore that major interest has risen concerning risk factors promoting this pathology.