Hip fractures are common among elderly individuals. Internal fixation with the intramedullary system has been widely used to treat intertrochanteric femur fractures. The Gamma 3 nail is a useful device for fixating trochanteric fractures of the proximal femur. We report a rare complication of medial pelvic penetration of the lag screw of a Gamma 3 nail two months after surgery. There was a complete separation between the nail body and lag screw, and the lag screw penetrated through the acetabulum into the pelvis. We report a case of unstable intertrochanteric fracture with intrapelvic penetration after surgical treatment with proximal femoral nailing and a case followed by fatal results.