We describe a 38-year-old male with abrupt onset of left hip pain. The diagnosis of transient osteoporosis of the hip was made on the basis of the clinical history and characteristic radiographic changes (osteopenia with indistinctness of the subchondral cortex). Magnetic resonance imaging demonstrated diffuse decreased signal in the proximal femur without localization to the femoral head and magnetic resonance findings were more obvious than those demonstrated by conventional radiographs. Radiographs and magnetic resonance imaging after cessation of symptoms were near normal. Magnetic resonance imaging may be helpful in evaluation of patients with acute hip pain.