The high reported incidence of deep venous thrombosis (DVT) in trauma patients has prompted surveillance venous duplex scanning of the lower extremities. We report our retrospective experience with 183 multiple trauma patients who were admitted to the surgical intensive care unit and underwent 261 surveillance venous scans. There were 122 men and 61 women whose average age was 38 years. All patients were treated prophylactically with either extremity pneumatic compression or subcutaneous heparin to prevent DVT. Most (87%) patients suffered blunt trauma and had either head (3%), spinal (3%), intra-abdominal (9%), or lower extremity (17%) injuries or a combination of injuries (68%). Almost two thirds of the patients had no symptoms suggestive of possible DVT. Of the 261 venous scans performed, 239 (92%) were normal, 16 (6%) were positive for proximal lower extremity DVT, and six (2%) showed thrombus limited to the calf veins. Patients with symptoms of lower extremity DVT were significantly more likely to have proximal DVT compared to those without symptoms (15% vs. 5%, p <0.05). Patients with spinal injuries also had a higher incidence of proximal DVT (18% vs. 6%, p <0.05). At current hospital charges, the cost to identify each proximal DVT was $6688. If surveillance duplex scans were performed on all trauma patients in the surgical intensive care unit, the national annual expense would be $300,000,000. Routine DVT surveillance is expensive and should be reserved for symptomatic patients or those with spinal injuries.