Two infants with subcutaneous fat necrosis had hypercalcemia that normalized during glucocorticoid treatment. The combination of hypercalcemia, normal concentration of 25-hydroxyvitamin D, an elevated concentration of 1,25-dihydroxyvitamin D, a suppressed parathyroid hormone level, and low-normal bone turnover indicated abnormal 1,25-dihydroxyvitamin D production with increased intestinal absorption of calcium. Unregulated production of 1,25-dihydroxyvitamin D by the granulomatous cells of fat necrosis may cause hypercalcemia.