Bone mineral contents of calcium urolithiasis patients (105 males and 52 females) were measured by the microdensitometry (MD) method, and the patients were divided into the MD normal group and the MD abnormal group. The patients were also divided into the group (21 males and 3 females) treated with thiazides for 1 year or more and the nontreated group to examine various factors in blood and urine. [Nontreated group] The rate of MD abnormality was higher in younger males. The rate tended to increase with age in females. Alkaline phosphatase values were significantly higher in MD abnormal group males than in MD normal group males. Urinary calcium excretion and PTH values were significantly higher in MD abnormal group females than in MD normal group females. Comparison of hypercalciuria and normocalciuria revealed no significant difference between the MD normal rate and the MD abnormal rate. Comparison of single of stone formers and recurrent stone formers also revealed no significant difference between the MD normal rate and the MD abnormal rate. [Treated group] PTH and alkaline phosphatase values were significantly higher in the treated group than in the nontreated group. Alkaline phosphatase values were significantly higher in the MD abnormal group. From the viewpoint of stone recurrence prevention, the monitoring of bones where the majority of calcium in the body is present is considered important besides behavior of calcium in blood and urine.