With the extension of human life span, osteoporosis is the second common epidemic disease in the world, second to cardiovascular disease. Therefore, the prevention and treatment of osteoporosis is an important issue in Taiwan because of its rapidly aging population. Osteoporosis is a disease that results in increased risk of fracture due to systemic low bone mass and the destruction of bone microarchitecture. Most menopausal women are caused by aging and lack of estrogen to enhance bone resorption, in addition to consider whether there are secondary causes such as steroid use. The clinical diagnosis of osteoporosis can be either fragility fractures or bone mineral density (BMD) measured by a dual energy X-ray absorptiometry (DXA). Treatment of osteoporosis involves proper lifestyle and medication. Bisphosphonates are one of the most commonly used drugs in the world for the treatment of osteoporosis, but more and more evidence shows that long-term use of bisphosphonates increases the risk of atypical fractures. This article reports a case of bilateral atypical femoral fractures in an elderly patient with systemic lupus erythematosus who took steroid control for a long time and bisphosphonates due to osteoporosis for about ten years. We will discuss the risk factors, drug use, further treatment, and follow-up.