Abstract Background: Alendronate is a bisphosphonate that is approved to reduce bone loss in glucocorticoid treated patients. In this paper, we present a case of femoral fracture following the use of Alendronate. Case presentation: A- 46 year old woman who was a known case of hemolytic anemia has been treated by prednisolone (with different doses from 7.5 to 75 mg/day), calcium-D 500 mg/day and alendronate 70 mg/week for 3 years. Despite improvement of bone density, she experienced a low truama femoral shaft fracture. Conclusion: This case shows a rare complication of treatment by alendronate. It may be needed to evaluate patients with long term usage of bisphosphonates for cortical thickness.