Musculoskeletal complaints are the most common presenting symptoms in most of the patients with systemic lupus erythematosus (SLE). However, periosteal new bone formation is an extraordinarily rare condition in SLE. We report a case of periosteal reaction in SLE. A 31-year-old woman with SLE presented with both knee pain. Radiographs revealed periosteal reactions in both femur and tibia and around the metaphysis of the right distal tibia. Periosteal reaction can be caused by benign or malignant lesions and infection. We cannot find any other cause of periosteal reaction in our case after thorough evaluations. Periosteal reaction in SLE might be associated with inflammatory vascular changes. This is the first report of periosteal reaction in SLE after the 1990s description and the first report in Korea.