Retardation of growth and maturation is a frequently observed complication after renal transplantation in children. It is attributed predominantly to the presently used immunosuppressive therapy. In four girls who were followed up to 28 months after transplantation the dose of prednisone was reduced to 1 mg/kg/day within six weeks. Between three and one-half and five months it was further changed to an alternate-day treatment schedule provided no signs of rejection were found and a stable renal function was present. With this treatment the incidence of rejection was not increased, all steroid side effects gradually subsided and the renal function remained normal. All four patients were growth retarded before operation. They continued or started to grow after transplantation; two girls reached the 50th height percentile within 12 months; the other two have shown considerable growth. Alternate-day prednisone therapy is an important modification of the presently used immunosuppressive treatment, facilitating medical and social rehabilitation and reducing the number of complications in children and adolescents.