The purpose of the study is to evaluate the efficacy and safety of the oral dose of YM150 for prevention of venous thromboembolism (VTE) in patients undergoing major abdominal surgery.

Inclusion Criteria:

• Patients after a major abdominal surgery
• Written informed consent obtained

Exclusion Criteria:

• Subject has history of symptomatic deep vein thrombosis and/or pulmonary embolism
• Subject has a hemorrhagic disorder and/or coagulation disorder
• Subject has had clinically important bleeding occurred within 90 days prior to the screening visit
• Subject has an active bacterial endocarditis
• Subject has uncontrolled severe or moderate hypertension, retinopathy, myocardial infarction or stroke
• Subject is receiving anticoagulants/antiplatelet agents
• Subject has a thrombocytopenia
• Body weight less than 40 kg at the screening