Venous thromboembolism, a collective term for pulmonary embolism and deep venous thrombosis accounts for a large amount of mortality and morbidity in hospitalized patients. Obesity has been considered as an important risk factor for the development of venous thromboembolism. Anticoagulation with fixed doses of low molecular weight heparin, anti-factor Xa inhibitors and unfractionated heparin is widely used in hospitals and has shown to be an effective measure in prevention of venous thromboembolism in multiple major randomized, double-blind controlled trials. Appropriate dosing of anticoagulation in obese patients is still controversial, since obese and morbidly obese population of patients is consistently underrepresented or often excluded from most clinical trials, raising a concern for adequacy of standard dosing in this high risk population.