Trauma patients are at exceedingly high risk for the development of deep venous thrombosis and pulmonary embolism. The incidence, pathophysiology, diagnosis, prophylaxis, and therapy of deep venous thrombosis and pulmonary embolism in the trauma patient are reviewed. The type of injury, systemic pertubations, and enforced immobility are important factors in pathogenesis. Patients with lower extremity injuries and spine fractures with paraplegia appear to be at highest risk. Orthopedic devices used to treat these injuries often preclude the conventional noninvasive diagnostic modalities. Further, hemorrhagic risk often impacts the judgment regarding the use of prophylactic measures as well as the therapy once deep venous thrombosis is diagnosed. Better data regarding the incidence of venous thromboembolism and the applicability of existing diagnostic, prophylactic, and treatment approaches in this population are needed. Accidents are responsible for over 140,000 deaths and approximately 70 million nonfatal injuries annually in the United States [1]. Most of the fatalities occur within hours of injury as a result of exsanguination or a lethal head injury, but approximately 20% survive for days or weeks [2], usually in the intensive care unit. The primary causes of late death are sepsis and multiple-organ failure [2]. Increasing evidence, however, suggests that pulmonary embolism (PE) is now becoming a leading cause of late death, especially in some high-risk groups [3][4][5].The increase in the incidence of PE is due in part to improvements in trauma care, which have lowered the early mortality rate [6-8], leaving more patients at risk for late death. In addition, autopsy examinations, used more frequently to audit trauma care systems [6,9], have documented an increase in clinically unsuspected deep venous thrombosis (DVT) and PE.This review was prompted because of the apparent increase in DVT and PE in the trauma population, and because the trauma patient presents very difficult and unique problems compared with the nontrauma patient with regard to the diagnosis, prophylaxis, and treatment of these disorders. In this review, we address the incidence, pathophysiology, diagnosis, treatment, and prophylaxis of DVT and PE in the trauma patient. We do not consider the entities of fat embolism or pulmonary microemboli as a cause of late pulmonary failure.