SummaryBackground and objectives Hyperphosphatemia and subclinical endotoxemia are important sources of inflammation in HD. Proinflammatory cytokines are strong correlates of soluble CD14 (sCD14) concentrations, an independent predictor of mortality in this population. We evaluated the effects of calcium acetate and sevelamer hydrochloride on serum inflammatory profile, endotoxin concentrations, and sCD14 levels in HD patients.Design, setting, participants, & measurements Prospective, randomized, open-label, parallel design trial. Fiftynine stable HD patients, 30 receiving sevelamer, and 29 receiving calcium acetate were evaluated. Serum levels of inflammatory parameters (high-sensitivity C-reactive protein [hs-CRP], TNF-␣, interleukin (IL)-1, -6, -10, and -18), as well as endotoxin and sCD14 concentrations, were measured at baseline and after 3 months of therapy.Results Serum IL-6 increased in patients receiving calcium acetate, whereas hs-CRP and IL-6 significantly decreased in subjects treated with sevelamer, with IL-10 experiencing a trend to increase (P ϭ 0.052). Serum endotoxin and sCD14 levels did not change after treatment with calcium acetate. However, these parameters decreased by 22.6% and 15.2%, respectively (P Ͻ 0.01), in patients receiving sevelamer. Multiple regression analysis showed that variation in serum endotoxin concentrations was the strongest factor associated with IL-6 change, whereas the only variables independently associated with changes in sCD14 levels were the variations in serum IL-6 and endotoxin concentrations.Conclusions Administration of the noncalcium phosphate binder sevelamer to maintenance HD patients is associated with a significant decrease in hs-CRP, IL-6, serum endotoxin levels and sCD14 concentrations.