Objective To explore the effects of sera from different dialysis modalities on TGF-β1 expression in human renal tubular epithelial cells. Methods We randomly assigned 24 uremic patients into hemodialysis (HD), high-flux hemodialysis (HFHD) and hemodiafiltration (HDF) groups. Blood sample was collected from the patients before and after the dialysis. Diacetylmonoxime method was used to determine the ratio of urea nitrogen before and after the dialysis, from which Kt/V value was calculated and the adequacy of hemodialysis was estimated. HK-2 cells were cultured with the patient sera before and after dialysis. TGF-β1 mRNA in these cells was measured by RT-PCR, and TGF-β1 protein in cultured supernatant of HK-2 cells was determined by ELISA. Results The Kt/V values of the 3 blood purification methods exceeded 1.2, indicating the adequate hemodialysis. The sera after HDF showed less effects on TGF-β1 mRNA expression in HK-2 cells and less TGF-β1 secretion from the cells (P<0.05) than the sera before HDF. However, these changes were not found from sera before and after HD and HFHD (P>0.05). Conclusion HDF can effectively eliminate the uremic toxin inducing fibrosis-associated cytokine expression. Therefore, we presume that HDF is capable to efficiently postpone the interstitial fibrosis in kidney.