A prediction of the end-stage renal disease (ESRD) population in Japan from 1980 to 2000 was made using a system dynamics model based on previously published estimates. It is estimated that the ESRD population will be 145,750 (1111 per million population (pmp)) by the year 2000, if renal transplantation gradually increases and finally reaches 3000 (22.9 pmp) per year by 2000. This number is approximately 1.8-fold greater than the 1987 ESRD population (80,075). On the other hand, the projected number of people with ESRD could be 157,350 (1199 pmp) if the promotion of renal transplantation is unsuccessful until 2000 and the number of renal transplants is 800 (6.1 pmp) per year up to that time. In conclusion, the promotion of renal transplantation requires urgent attention to ensure adequate suppression of any future increase in the ESRD population in Japan.