Deep venous thrombosis (DVT) is an important clinical condition accounting for 600,000 hospitalized patients in North America per year. Signs and symptoms of DVT are nebulous and often absent. Pulmonary embolus is often a coexisting condition and is most often caused by DVT. Both require anticoagulation and possibly thrombolytic therapy. There is a long list of risk factors that predispose a patient to DVT including cancer, cardiac disease, and hereditary conditions. This article examines predisposing factors, diagnostic tools, treatment, and sequela of DVT.