The aim of the study was the objective evaluation of the hearing organ in children. Seven children aged 6-17 with end stage renal failure treated by haemodialysis were examined. Four- to five-hour dialyses were performed 2-3 times a week. Pure-tone audiometry was normal in five children. The reactions of brain stem responses (latency and interpeak latency) were analysed before and after haemodialyses. We conclude that the ABR differences were connected with biochemical parameters of uraemia. The present study is a preliminary one and will be continued in the future.