Infectious complications within 1 year of cadaveric kidney transplantation were compared in 45 patients treated with azathioprine, prednisone, and antilymphocyte globulin and 38 patients treated with cyclosporine and prednisone. Although there was no difference in the 1 year patient or graft survival rate, cyclosporine-treated patients had significantly fewer wound infections, infection-related transplant nephrectomies, and infection-related graft failures than azathioprine-treated patients. The cyclosporine-treated diabetic recipients had more nonviral pneumonias and opportunistic infections but fewer cases of infection-related transplant nephrectomy than did the azathioprine-treated diabetic patients. Our data suggest cyclosporine is associated with reduced infectious morbidity after cadaveric kidney transplantation in nondiabetic patients.