This doctoral thesis was designed to compare the effects of treatment conducted in the group of patients hemodialyzed who were maintained 6 months on a dialysis using LF dialyzers with polysulphone membrane, and who then for the period of next 6 months continued on a dialysis therapy using HF dialyzers with the helixone membrane. 60 patients took part in the observation. The age of patients was 60,73±15,75 years on average. In the analysis significant higher rates of indices spkt/V and URR% during HF dialysis versus LF dialysis were observed. Statistically significant difference was also observed within the scope of the average hemoglobin concentration ( Hb LF 11,09±0,89 versus Hb HF 11,42±0,98; p<0,01). In the analysis of calcium-phosphate concentration in blood, the obtained average product scores of Ca x P presented a better control of imbalance of Ca-P concentration in the period of HF dialysis versus LF (p<0,02). Statistically significant higher (MAP) parameters were demonstrated before HD HF versus HD LF, which may be beneficial in the reduction of the tendency to intradialytic hypotension among patients treated with HF dialysis. The use of HF dialyzers with the helixone membrane may bring particular benefits in terms of: the improvement of the adequacy of dialysis, the improvement of anemia control, the reduction of disturbances of Ca x P concentration in the blood, the gain of greater hemodynamic stability of the cirulatory system.