Calcium metabolism was studied in hemodialyzed patients with diabetes mellitus nephropathy (HD/ DM) and in hemodialyzed nondiabetic patients with chronic glomerulonephritis (HD/non-DM). Incidence of bone changes visible in X-ray films, assessed by changes in the lamina dura and trabecular patterns of mandibulae, was less in HD/DM than in HD/non-DM patients. Serum c-terminal parathyroid hormone was significantly lower in HD/DM than that in HD/non-DM. Serum calcitonin was higher in HD/DM than that in HD/non-DM. The lower level of c-terminal parathyroid hormone would be a reason that bone changes were less in HD/DM than in HD/non-DM patients.