The efficacy of the pulse oximeter was evaluated in lieu of multiple arterial blood gas (ABG) determinations as a screening method for the early diagnosis of hypoxemia and clinical fat embolism syndrome. A prospective analysis was performed on 43 patients with long bone and pelvic fractures without any associated chest wall, head, or intraabdominal trauma. A standard pulse oximetry reading was obtained initially within 12 hours of injury and at 24-hour intervals thereafter until the patient had been observed for 72 hours. Fifteen patients were hypoxemic with an oxygen-hemoglobin (O2-Hb) saturation less than or equal to 94%. All hypoxemic patients were evaluated by ABG measurements that demonstrated the expected correlation with the pulse oximetry readings. These patients were subsequently managed with an intensive pulmonary care regimen. Hypoxemia resolved in all patients within 48 hours of the initiation of treatment. The pulse oximeter is an efficient and reliable screening device to identify patients with clinically unrecognized hypoxemia.