We describe a 79-year-old woman with rheumatoid arthritis who suffered from subchondral insufficiency fracture of the femoral head (SIF) and contralateral femoral neck fracture. Radiographs obtained two months after the onset of thigh pain showed collapse of the right femoral head and contralateral femoral neck fracture. MRI revealed a subchondral serpiginous low-intensity band in the right femoral head on the T2-weighted image. This case report suggests that SIF should be considered in the differential diagnoses of rheumatic patients who suffer from thigh pain without antecedent trauma.