Case: We present a rare case of insufficiency fracture at the level of the distal interlocking screw following union of an intertrochanteric hip fracture. A 74-year-old woman reported chronic thigh pain for 1 month. She had a history of an osteoporotic stable intertrochanteric fracture that was successfully treated with a short intramedullary nail 3.5 years prior. However, after union, the neck-shaft angle of the femur changed from 125° to 117°. She had been on alendronic acid therapy to prevent a secondary osteoporotic fracture. A recent radiograph and bone scan suggested an insufficiency fracture around the level of the distal interlocking screw. Revision surgery with a long intramedullary nail was performed, and complete union was observed 1 year postoperatively. Conclusion: This case suggests that subsequent insufficiency fracture can occur after complete union of an intertrochanteric hip fracture. Physicians should be aware of the possibility of a stress fracture when a patient has thigh pain after an intertrochanteric fracture has healed following repair with a short intramedullary nail.