Inclusion Criteria: - Subjects with chronic kidney disease who have received dialysis for at least one month before the first dose of study medication and are clinically stable. - Adults at least 18 years of age who have given written informed consent. - Out of target PTH values, defined as the most recent historical measurement of biPTH > 160 pg/mL within 3 months prior to informed consent signature. - Serum calcium >/= 8.4 mg/dL within one month prior to informed consent signature. Exclusion Criteria: - Unstable medical condition, defined as having been hospitalized within 30 days before Day 1, or otherwise unstable in the judgement of the investigator. Hospitalization solely for dialysis vascular access revision does not qualify as an unstable medical condition. - Parathyroidectomy in the 3 months before Day 1. - Current gastrointestinal disorder that may be associated with impaired absorption of orally administered medications or an inability to swallow tablets. - Use of investigational drug or device or participation in trial of investigational drug or device (except experimental dialysis machines) within 30 days of enrollment into the study. Any investigational procedures. - Females of child-bearing potential who are pregnant (e.g., positive serum pregnancy test) or are breast feeding. Females of child bearing potential who refuse to use highly effective contraceptive measures (as determined by the investigator) throughout the study. - Hypersensitivity to Sensipar or any of its components. - Previously participated in this or any other Sensipar study, or received/is receiving Sensipar as a commercially available product. - Disorder that would compromise the ability of the subject to give written informed consent and/or to comply with study procedures.