The bone mineral status of fifty-one children with diabetes mellitus was studied by single photon absorptiometry. The mean bone mineral content was 13% below values predicted by age, sex, height, and weight. Those children whose diabetes was one year or less in duration were as osteopenic as those whose diabetes was of longer duration. The demineralized children received a higher daily insulin dose than others. No association was noted between the degree of skeletal demineralization and sex, statural growth, renal function, and serum calcium and phosphorus. No significant changes in bone mineral content were noted longitudinally.