Deep vein thrombosis (DVT) of the lower limb is a serious condition. It causes mortality in the short- term as a result of pulmonary embolism that attributes to 10% of hospital deaths, and severe morbidity in the long-term resulting from post- thrombotic syndrome (PTS). Despite the use of anticoagulation therapy, PTS develops in 25-50% of DVT patients, impairing their quality of life. Many patients require either prolonged or life-long therapy to manage PTS. Thrombolytic therapy can provide an opportunity for restoration of venous patency by removing of the thrombus and preserving of venous valve function. This therapy can potentially prevent PTS. Thus, this book provides an overview of DVT: it's causes, pathophysiology, diagnosis and treatment options particularly thrombolytic therapy. I wish that this book could help physicians to understand the nature of the disease as well as it's proper management to choose the best way to cure their patients.