Haemodynamic changes in children examined by reocardiography impedance method were compared for 15 sessions performed with new capillary cuprophan dialysers and 15 sessions performed with reused ones (fourth use). Subsequent parameters of cardiovascular system performance were assessed: CI-cardiac index, SI-stroke index, ACI-acceleration index, SVRI-systemic vascular resistance index, EF-ejection fraction, TFC-thoracic fluid conductivity, MAP-mean arterial pressure. Significant differences in MAP, EF, TFC, ACI values between the sessions with the first and the fourth use of cuprophan dialysers were noted. Marked increase of cardiac output during the acetate haemodialysis was observed as the result of afterload declining by lowering systemic vascular resistance during the session with new and reused cuprophan dialysers. Contractility of myocardium and ejection fraction significantly increased during the session performed on new dialysers. Ejection fraction remained unchanged and myocardial contractility slightly improved during the fourth use of cuprophan dialysers.