Objectives: The number of elderly patients and those with a poor nutritional status at our dialysis clinic is increasing. The nutritional status of some of these patients are not significantly improved through intensive medical nutritional therapy. The objective of the present study was to investigate the effectiveness of using Polyflux® H membrane (PF), a blend of polyamide, polyarylethersulfone and polyvinylpyrrolidone with the three layered structure, which has been reported to allow lower albumin leakage for improving the nutritional status of the patients. Methods: We conducted a retrospective analysis of 27 of our outpatients undergoing hemodialysis in whom the nutritional status was considered as being poor, and the improvement of nutritional status was not significant after at least one month of nutritional therapy. The patients were switched to the PF hemodiafilter. We compared the kt/v, CRP, Alb(g/dl), Cr(mg/dl), nPCR(g/kg/day), GNRI, and %CGR(%) every 2 weeks after the switch. Results: There was no significant difference in the dialysis dose (kt/v, Cr) or CRP between before and after the switch to PF. Alb level increased significantly from 3.6 to 3.7 at 13-24 weeks after the switch (p=0.002). The GNRI increased from 94 to 95 at 13-24 weeks after the switch (p=0.042). There was no significant difference in the nPCR or %CGR. Conclusions: The switch to PF resulted in a significant increase of the Alb and GNRI, while there was no change in the nPCR or %CGR. Long-term use of PF combined with proper nutritional intake may be expected to improve the nutritional status and prognosis of elderly dialysis patients.