OBJECTIVE The effect of hemodialysis (HD) to change the viral load of hepatitis B virus (HBV) in uremic patients with chronic HBV infection has never been studied. In this study, we investigated the HBV viral loads and their changes between the HD procedure in the uremic patients. METHODS A total of 38 chronic HBV-infected uremic patients were enrolled, but eight cases were excluded due to HCV co-infection and under anti-viral therapy. To evaluate the HBV DNA levels and their changes through the course of HD, we quantified serial serum samples from each patient immediately before HD, at the end of HD, and 48 hours later--immediately before the next HD. RESULTS Most of our HBV-infected uremic patients had a relatively lower HBV viral load; 80% cases with HBV DNA <or=4 Log(10)copies/mL, in comparison with the Taiwan epidemiologic study for community base HBV carriers. There was no significant difference of HBV DNA level between HBeAg-positive and -negative patients, but a significant higher DNA level in the high ALT group (p = 0.029) and liver cirrhosis patients (p = 0.002). The mean HBV DNA levels, before and after HD, respectively, in our 30 patients were 3.823 +/- 1.130 Log(10)copies/mL and 3.686 +/- 1.114 Log(10)copies/mL. It was a significant decrease on HBV DNA level in chronic HBV-infected patients through HD procedure (p = 0.004). The mean HBV DNA level of two days after HD was 3.702 +/- 1.094 Log(10)copies/mL, which was not significantly different from the HBV DNA level before (p = 0.076) or after (p = 0.267) HD; however, the mean reduction of HBV DNA by a single HD was 0.11 +/- 0.38 Log(10)copies/mL. Patients with low viral load also had a significant high platelet count (p = 0.03), high serum albumin (p = 0.016), and low AST level (p = 0.002). CONCLUSIONS Most uremic patients with chronic HBV infection under regular HD in Taiwan had a relatively lower viral load, of which the major mechanism could be due to the elimination of serum HBV viral load by the HD procedure.