The frequently encountered disorder of venous thromboembolism (VTE) can cause serious morbidity and even death. Nevertheless, in more than 70% of patients who die of pulmonary embolism (PE), the diagnosis is not considered before death. Thus, clinicians should have a high index of suspicion for VTE, especially in high-risk patients. Some risk factors for VTE are a recent surgical procedure and general anesthesia, immobilization, congestive heart failure, previous PE, pregnancy, and oral contraceptive use. Before therapy can be initiated, a definitive diagnosis of VTE must be established. An algorithm for assessing patients with possible VTE is presented; decisions about proceeding with various studies are based primarily on the clinician's degree of suspicion for the presence of PE and the findings on a ventilation-perfusion scan. Elevation of the patient's legs before, during, and after a surgical procedure is a simple measure that may substantially decrease the occurrence of PE.