The chapter begins with practical tips on prevention of Deep vein thrombosis, like early ambulation. Pathophysiology of phlebothrombosis, fibrinolytic system and chronic venous insufficiency is described in some detail. Diagnostic modalities like impedance plethysmography, venography, etc. are described. Prevention and treatment of DVT is described, including types of heparin therapy with monitoring of therapy. Fibrinolytic treatment also merits mention. Guidelines on individualizing therapy according to the precise diagnosis are given.