Abstract:  Subcutaneous fat necrosis is an inflammatory disorder of adipose tissue. Although patients need long-term follow-up to prevent hypercalcemia, the prognosis is generally favorable. We herein present a case of a newborn who developed subcutaneous fat necrosis–related hypercalcemia after hypothermia treatment for hypoxic ischemic encephalopathy. Widespread use of hypothermia treatment for hypoxic ischemic encephalopathy in the neonatal intensive care unit may increase the risk of developing subcutaneous fat necrosis and subsequently hypercalcemia. Great care should be taken to recognize skin findings early in newborns receiving hypothermia treatment, and those diagnosed with subcutaneous fat necrosis require close follow-up because they are at risk for developing hypercalcemia.