Cyclosporin A (CyA) is an immunosuppressive agent which has been used in children following kidney transplantation since 1982. The paediatric experience made with CyA in a single centre is reported here. Forty-seven children, ranging in age from 2 to 16 years, were given transplants between September 1982 and May 1986 and received CyA with low-dose prednisolone for immunosuppression. The mean cold ischaemia time of the grafts was 20.9 h. Under routine volume expansion during and 24 h posttransplantation, 40 grafts (85%) functioned immediately. Acute rejection episodes occurred with the highest frequency during the 1st month (0.6 rejection/patient). The actuarial survival rate for patients was 98% after 3 years. Graft survival was 92% after 1 year, 87% after 2 years and 78% after 3 years. The side-effects observed with CyA were hypertrichosis (38%), neurological complications (21%), and infections (17%). One girl of 16 years developed benign mammary fibroadenomas. Hypertension was common (60%), but less so than seen with conventional therapy (83%). Graft function was reduced. The mean creatinine clearance at 6 weeks after transplantation was 60 ml/min per 1.73 m2, after 1 year was 46.4 ml/min per 1.73 m2 and after 2 years it was 42.5 ml/min per 1.73 m2. Twenty-nine children with functioning grafts of at least 1 year could be evaluated for growth performance and normal or even catch-up growth could be demonstrated for the whole group. The individual annual growth rates expressed by standard deviation score (SDS) remained stable or even improved 3 years after kidney transplantation. Longer periods of follow-up are necessary to confirm whether the advantages concerning survival rates and growth rates persist over time and will outweigh the side-effects of CyA treatment.