It is generally accepted that renal transplantation as a routine therapy for terminal stage renal patients has various medical advantages over chronic haemodialysis. A comparison of costs of both types of treatment clearly demonstrates a considerable difference also in favour of the former. This comparison is based on patient data from the Leyden University Hospital and on the tarrifs agreed upon by the Dutch Public Health Insurance Companies for haemodialysis treatment in 1973. (In this article only cost of center dialysis has been compared with cost of transplantation. In Holland, so far, no comparable data on the cost of home dialysis are available.) Renal transplantation, including 12 months of post-operative care, requires some Dfl. 45,000 (or + 18,000) whereas one year of chronic center haemodialysis cost Dfl. 65,000 (or + 26,000). The cost of treatment of a patient with a well-functioning graft in the second and following years normally does not exceed Dfl. 8,000 (or + 3,200) per year. These figures demonstrate the enormous economic advantage of transplantation as compared to chronic center haemodialysis, and that together with the medical advantages of transplantation should be sufficient reason to promote transplantation.