A randomized, cross-over, open-label study will be conducted to evaluate the equivalency, safety and tolerability of sevelamer once per day dosing, given with the largest meal, compared with standard three times per day dosing, in hemodialysis patients previously using sevelamer. Following a two week Run-In period, a total of 24 patients will be randomized to one of the following treatment sequences:

1. sevelamer dosed once a day with the largest meal followed by standard three times per day dosing with meals
2. sevelamer dosed three times per day with meals followed by once a day dosing with the largest meal. Patients will maintain a fixed daily dose throughout both treatment periods based on the most recently prescribed sevelamer dose prior to screening.

Inclusion Criteria:

• life expectancy of at least 12 months,
• patients have received hemodialysis three times per week for 3 months or longer,
• patients maintained on sevelamer in a daily dose of ≤ 9,600 mg as their only phosphate binder with serum phosphorus concentrations at the last two measurements between 3.0 and 6.5 mg/dL (0.97 and 2.10 mmol/L).

Exclusion Criteria:

• active bowel obstruction,
• dysphagia,
• swallowing disorders,
• severe gastrointestinal motility disorders,
• active ethanol or drug abuse (excluding tobacco),
• need for antidysrhythmic or antiseizure medications used to control these conditions,
• poorly controlled diabetes mellitus or hypertension,
• active vasculitis,
• active malignancy other than basal-cell carcinoma,
• HIV infection,
• any clinically significant unstable medical condition as judged by the investigator.