Charts of all patients undergoing reamed femoral nailing for traumatic femoral fractures at two level I trauma centers over 5 years were reviewed. Seven patients who met the criteria for morbid obesity (> or = 200% of ideal body weight or > or = 100 lb over ideal body weight or body-mass index > or = 37 kg/m2) were identified. There were four women and three men, average age 41.8 years, average weight 300.7 lb. The Body-Mass Index, considered the best measure of relative obesity in adults, averaged 49.2 kg/m2 (normal, 20-25 kg/m2; morbidly obese > or = 37 kg/m2). There were four femoral shaft fractures, two subtrochanteric, and one combined femoral neck-femoral shaft fracture. Surgical procedures averaged 3.8 hours in duration with an average blood loss of 1100 mL. Intraoperative and postoperative complications were numerous; difficulty in establishing a start point resulted in two fractures of the greater trochanter, and one partial trochanteric osteotomy was necessary for access in a third patient. Postoperatively two patients developed wound infections that required antibiotic treatment plus wound debridement, and four patients developed complications related to deep vein thrombosis with one fatal pulmonary embolus documented. All femoral fractures in the six surviving patients united.