A female infant developed extensive subcutaneous fat necrosis 3 weeks following induced hypothermia used as an adjuvant in cardiac surgery. All lesions resolved without sequelae within 4 months. In this article we discuss the various causes of panniculitis in infants and the relevance of each cause to our patient. We believe that an underlying defect in composition and metabolism of fat, coupled with a variety of exogenous and endogenous stresses, can precipitate subcutaneous fat necrosis in infants. These stresses include physical trauma (e.g., hypothermia), poor nutrition, infection, and metabolic abnormalities.