We studied 275 renal replacement therapy (RRT) patients in a Danish county (population 329,000) from January 1st 1979 to June 30th 1994. Incidence, prevalence and age of new patients increased. The fraction of patients with diabetic nephropathy also increased. Patient survival remained constant (five-year survival 62% for patients observed for more than 90 days). The total number of new patients entering haemodialysis and peritoneal dialysis seemed to be reaching a constant level, that could be calculated using a logistic function. The fraction of patients leaving therapy remained constant over the years and was higher for peritoneal dialysis than for haemodialysis (32 vs. 20% per year). The future prevalence can be estimated by combining these two last findings.