In a randomized controlled clinical trial, 117 recipients of a kidney transplant were treated with cyclosporine (15-17 mg/kg/day) either alone or with prednisolone 0.3 mg/kg/day in addition. There were no exclusions and all patients have been followed-up from 14 to 39 months. No differences in the survival of the patients or their transplants were seen between the two groups. Actual survival of first cadaver grafts was 73% at one year in the group receiving cyclosporine alone and 76% in the group with added steroids. Survival of second or third grafts in the steroid group was somewhat worse but not significantly so. All 6 recipients of living-donor grafts are currently alive with good function. Infective complications were significantly less common in the group not receiving routine steroids, and these patients were also at less risk of developing a changed facial appearance. However, half the patients in this group have subsequently required steroids because of previous rejections, and cyclosporine nephrotoxicity has been significantly more common. Nonetheless, we have found no overall advantage in combining cyclosporine with low-dose maintenance prednisolone, and we advise that patients undergoing renal transplantation receive cyclosporine alone in the first instance.