In a patient with DVT, a clot forms in the large veins of the extremities, typically the leg, which can lead to a pulmonary embolus, a potentially life-threatening medical problem. Risk factors include provoking factors such as recent surgery, acquired factors such as obesity or cardiovascular disease, and genetic factors such as protein C or S deficiency. The Wells DVT score is a clinical scoring system that allows the assessment of the pretest probability of DVT. However, clinical gestalt has been found to be equally accurate. This can then guide the clinical work-up of the patient, with low and moderate pretest probabilities, allowing one to start with D-dimer testing, versus high probability, requiring one to begin with lower extremity US. The current trend in treatment of DVT is the novel oral anticoagulants as they can be given at fixed doses, do not require laboratory monitoring, and have a better safety profile than warfarin. Pregnant patients, those with cancer, as well as many with recurrent DVT are treated with low-molecular-weight heparin. Most patients with DVT may be treated as an outpatient. A small percentage of patients with severe DVT may benefit from catheter-directed thrombolysis. This review contains 1 figures, 2 tables, and 48 references. Key Words: anticoagulants, D-dimer, diagnostic ultrasonography, DVT, low molecular weight heparin, postthrombotic syndrome, unfractionated heparin, warfarin