Approximately 45 hyperphosphatemic CKD patients not on dialysis will be entered into this study at approximately 20 sites within Europe and 5-10 in Australia. The purpose of this study is to determine if sevelamer carbonate tablets dosed three times a day (TID) is an effective treatment for the control of serum phosphorous levels in hyperphosphatemic CKD patients not on dialysis. Total length of participation is approximately 14 weeks.

Inclusion Criteria:

• A minimum of 120 male and female patients with chronic kidney disease not requiring dialysis will be screened for participation in the study.
• Men or woman 18 years of age or older
• If currently taking phosphate binder(s), willing to stop this and enter a 2 week washout period
• Willing to avoid any intentional changes in diet such as fasting or dieting
• Have the following central laboratory measurements: 1. If not on a phosphate binder, a serum phosphorus measurement ≥ 5.5 mg/dL (1.76 mmol/L) at Screening (Visit1). 2. If taking a phosphate binder(s) at screening, a serum phosphorus measurement ≥ 5.5 mg/dL (1.76 mmol/L) after the two-week washout period at Visit 1a (Day 0).
• At Screening (Visit 1), have the following central laboratory measurements: 1. 25-hydroxyvitamin D ≥ 10 ng/mL 2. iPTH ≤ 800 pg/mL
• Willing and able to take sevelamer carbonate alone as a phosphate binder for the duration of the study
• Willing and able to maintain screening doses of lipid medication, 1,25 dihydroxyvitamin D, and/or cinacalcet for the duration of the study, except for safety reasons
• Willing and able to avoid antacids and phosphate binders containing aluminum, magnesium, calcium or lanthanum for the duration of the study unless prescribed as an evening calcium supplement
• If female and of childbearing potential (pre-menopausal and not surgically sterile), willing to use an effective contraceptive method throughout study, which includes barrier methods, hormones, or IUDs
• Expecting not to initiate dialysis for the duration of this study
• Considered compliant with phosphate binders (if applicable)
• Willing and able to provide informed consent
• Has not participated in any other investigational drug studies within 30 days prior to enrollment,
• Level of understanding and willingness to cooperate with all visits and procedures as described by the study personnel

Exclusion Criteria:

• Active bowel obstruction, dysphagia, swallowing disorder or severe gastrointestinal (GI) motility disorders
• Active ethanol or drug abuse, excluding tobacco use
• Use of anti-arrhythmic or anti-seizure medications for arrhythmia or seizure disorders.
• In the opinion of the investigator, patient has poorly controlled diabetes mellitus, poorly controlled hypertension, active vasculitis, HIV infection, or any clinically significant unstable medical condition
• Pregnant or breast-feeding
• Evidence of active malignancy except for basal cell carcinoma of the skin
• Unable to comply with the requirements of the study
• Known hypersensitivity to sevelamer or any constituents of the study drug
• Any other condition, which in the opinion of the investigator will prohibit the patient's inclusion in the study