Stress fractures occur when the loads applied to a bone exceed the mechanical resistance and fall into two groups. Fatigue fractures, in which abnormal mechanical stress is applied to a normal bone, and insufficiency fractures, in which fracture occurs when stress of normal activity is applied to a bone that has decreased elastic resistance. Femoral shaft insufficiency fractures are reported rarely in patients with postmenopausal osteoporosis. We report a case of repetitive insufficiency fractures of the femoral shaft in 70 year-old female with marked osteoporosis.