AIM: This study investigates the difference in the incidence of renal replacement therapy (RRT) between Flanders and the Netherlands and possible explanations for this difference. METHODS: End-stage renal disease incidence data were obtained from the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA). Additional sources were the National Institute of Statistics (NIS), the Central Bureau of Statistics (CBS), the Organisation for Economic Cooperation and Development (OECD) health data and the WHO Health For All database (WHO-HFA). RESULTS: There is remarkable difference in incidence rate of RRT between Flanders and the Netherlands, with a higher rate in Flanders. This difference is already present in patients aged 45-64 years and increases with age, being >2-fold higher in subjects of >/= 75 years. With respect to the renal diagnoses leading to need for RRT, a higher share of especially diabetes mellitus type 2 and renovascular disease was observed in Flanders. Remarkably, the difference in incidence rate of RRT is not associated with a difference in survival on RRT, not even in the elderly, arguing against a restricted access to RRT in the Netherlands. In the general population, the expected number of healthy life years at birth is lower in Belgium than in the Netherlands, and in Belgium, the hospital discharge rates for diabetes, acute myocardial infarction and cerebrovascular accident and the number of coronary bypass procedures and percutaneous coronary interventions per capitum is higher, as is the prevalence of obesity. CONCLUSION: Our data do not support the assumption that the differences in RRT incidence in the elderly between Flanders and the Netherlands are due to a more restricted access to RRT in the Netherlands but may be due to differences in underlying comorbidity and life style between the two populations.