Twenty-four patients suffering from fat embolism syndrome, severe enough to warrant transfer to an artificial ventilation unit, are reviewed. All developed the condition following trauma. Five patients were managed with oxygen therapy and sedation, but the other 19 needed intubation and ventilation to achieve adequate arterial oxygenation. In spite of intensive supportive therapy, 6 patients (who had all required ventilation) died, one due to heparin therapy, the others from progression of the syndrome. A poor prognosis seemed to be associated with young age, a rapidly progressive condition and a continued need for 100 per cent oxygen after institution of artificial ventilation. There seemed to be no relationship between outcome and severity of injury, type of surgical management and time of onset after injury. The clinical features of these patients are discussed with reference to the many unanswered questions that surround this condition.