The aim of this study was to examine the therapeutic effect of hypocalcemic stimulation caused by sevelamer hydrochloride (SH) administration on adynamic bone disease (ABD). The subjects were 28 maintenance hemodialysis (HD) patients who had remained in ABD state in spite of no administration of vitamin D(3) since HD induction (15 males and 13 females;12 diabetic patients and 16 non-diabetic patients). The mean age was 61.8+/-9.5 years and the mean HD duration was 5.5+/-3.9 years. The calcium concentration in the dialysate was 3.0 mEq/L. We made the final daily dose of SH after two months the same as the first daily dose of calcium carbonate (CC) in the following manner. At first we administered only CC at breakfast and lunch and SH at supper. And for the next two weeks we administered CC at breakfast and SH at lunch and supper. And for the final two weeks we administered only SH. After that we increased the dose of SH as much as possible. We evaluated the therapeutic effect of the above treatment on ABD using intact-osteocalcin (iOC) [Teijin. Tokyo] as a marker before and 6, 12 months after the beginning of the replacement. If iOC Ievel of 30 to 70 ng/mL showed normal tumover bone (NTB), 5 cases (17.9%) changed into NTB in 6 months. 9 cases (32.1%) changed into NTB in 12 months and one case (3.6%) changed into ostitis fibrosa in 12 months. It is thought that SH is effective for the treatment of ABD but we have to be careful for ostitis fibrosa.