 In thromboprophylaxis studies, including those investigating enoxaparin 40 mg once daily, morbidly obese patients greater than or equal to 35 kgm2 have been grossly under-enrolled. This is problematic for several reasons. First, the drug distribution is weight dependent and therefore, anticoagulant levels will differ according to a patients weight. 5 Secondly, the FDA approved doses are fixed doses that do not take into account body weight. Thirdly, obese patients are at greater risk for failure in preventing VTE and obese patients are probably at greater risk for developing VTE. 6 Lastly, morbidly obese patients are becoming quite common as the population as a whole is becoming more obese. 