Objective:Hyperphosphatemia is a prognostic factor for morbidity and mortality inhemodialysis patients. Bixalomer is a non –absorbable polymer that decreases serumphosphate levels by binding phosphate in the gastrointestinal tract. In this practice–based post –marketing surveillance, we examined the efficacy and safety of bixalomer in patients on hemodialysis with hyperphosphatemia. Methods:This was a non –comparative, prospective observational study. The clinical end points were serum phosphate level, serum calcium level, serum intact parathyroid hormone (iPTH) level and incidence of drug– related adverse reaction. Results:Of 314 patients who administered bixalomer, 79.0% of patients (n=284)complied with the initial dose (500 mg three –times daily). The serum phosphate level decreased continuously from the baseline (7.05±1.257 mg/dL) until Month 3 (or at the time of discontinuation, 5.98±1.385 mg/dL), while the serum calcium level remained unchanged during the observation period. The iPTH level decreased from the baseline(median 159 pg/mL) until Month 3(or at the time of discontinuation, median 147 pg/mL). The adverse events for which a causal relationship with bixalomer was not ruled out occurred in 9.6% of patients and the major adverse events included constipation(3.8%) and diarrhea(1.6%). Conclusions:Bixalomer reduced serum phosphate level without affecting serum calcium level and was well tolerated, suggesting that bixalomer based therapy would be appropriate for the treatment of hyperphosphatemia in dialysis patients(ClinicalTrials.gov: NCT01901107).