Coronary artery bypass surgery was performed in two patients who had had renal transplantation. They had been taking immunosuppressive therapy. There were some problems in the management of these patients including prevention of postoperative infection, renal damage due to cyclosporin, and rejection of the transplanted kidney. Immunosuppressive therapy was continued under the meticulous monitoring of blood cyclosporin levels, blood T-cell subsets, markers of infection such as antiviral titers. The anticipated problems were not encountered in both cases. This is the first report in Japan which describes successful coronary artery bypass surgery for kidney transplant recipients.