A 66-year-old woman receiving continuous ambulatory peritoneal dialysis developed acute respiratory distress 12 hours after a fall. Blood gas analysis revealed hypoxia (PaO2 67.7 torr) and metabolic acidosis with an increased anion gap, consistent with lactic acidosis (lactate, 86.5 mg/dL; normal range, 4.0-16.0). Magnetic resonance imaging showed a lumbar vertebral body fracture. On the fourth hospital day, the patient died of multiorgan failure and disseminated intravascular coagulation. Postmortem studies revealed fat emboli in the systemic circulation, ie, fat embolism syndrome. Diagnosing fat embolism syndrome can be difficult in patients on dialysis or in those with collagen vascular or pulmonary diseases.