Deep vein thrombosis is a common condition that is often difficult to diagnose and may be lethal when allowed to progress. However, early implementation of treatment substantially improves the disease prognosis. Therefore, care must be taken to both acquire an accurate differential diagnosis for patients with symptoms as well as to screen at-risk asymptomatic individuals. Many diagnostic tools exist to evaluate deep vein thrombosis. Compression ultrasonography is currently the most effective diagnostic tool in the emergency department, shown to be highly accurate at minimal expense. However, limited availability of ultrasound technicians may result in delayed imaging or in a decision not to image low-risk cases. Many studies support emergency physiciansas capable of accurately diagnosing deep vein thrombosis using bedside ultrasound. Further integration of ultrasound into the training of emergency physicians for use in evaluating deep vein thrombosis will improve patient care and cost-effective treatment.