In a prospective study three different immunosuppressive schemata after renal transplantation were compared. In group A (47 patients) conventional treatment with azathioprin and steroids was administered; in group B (47 patients) antilymphocyte globulin (ALG) was additionally given for three weeks. In group C (47 patients) ALG-azathioprin-steroid administration lasted for a mean of nine days after the transplantation, followed by ciclosporin. One-year transplant survival rate was 59.6% in group A, 70.2% in group B and 89.4% in group C; one-year patients survival rate 95.7%, 89.4% and 100%, respectively. Thus conventional immunosuppression with ALG followed by ciclosporin was statistically significantly superior to the other two treatment schedules, both with respect to patient and transplant survival. This was also true of postoperative dialysis rate, which was lowest in group C, at 17%, compared with group A (85.1%) and group B (42.6%). Under the chosen study conditions there was no evidence of a negative effect of ciclosporin on long-term renal function.