Cinacalcet, an allosteric modulator of the calcium sensing receptor, effectively reduces serum parathyroid hormone (PTH) in patients with secondary hyperparathyroidism. It is not well known whether bone mineral density (BMD) of hemodialysis patients with secondary hyperparathyroidism is altered after cinacalcet treatment. The BMD in the distal 1/3 of the radius and in the ultradistal radius, which are enriched with cortical and cancellous bone, respectively, was examined by dual X-ray absorptiometry, 1 year prior to, at the start, and 1 year after cinacalcet treatment, in 61 patients. The BMD of both the distal 1/3 and ultradistal radius decreased significantly in the year prior to cinacalcet treatment (p < 0.01). However, the BMD at either site did not change significantly in the year after cinacalcet treatment. The annual changes in the BMD of the distal 1/3 radius increased significantly from -0.023 ± 0.029 g/cm2/year to -0.002 ± 0.033 g/cm2/year, prior to and after cinacalcet treatment, respectively; however, the annual changes in the BMD of the ultradistal radius did not change significantly prior to and after cinacalcet treatment. There was a significant association between cinacalcet treatment and reduction in BMD loss in patients with secondary hyperparathyroidism. Cortical bone, rather than cancellous bone, was particularly affected by cinacalcet treatment.