The ideal anticoagulant agent would have a fixed oral dose without need for dose adjustment, a wider therapeutic window than that of warfarin, and acceptable bleeding risks without the need for routine coagulation monitoring. Ximelagatran is a new oral agent that, when converted to its active form, melagatran, directly inhibits thrombin, thus blocking its activity and modulating several of its key functions. For the prevention of venous thromboembolism after orthopedic surgery, treatment of venous thromboembolism, and prevention of stroke in patients with atrial fibrillation, clinical trials indicate that ximelagatran meets the criteria for a superior anticoagulant.