The authors report 3 cases of spinal cord compression by vertebral collapse related to osteonecrosis. Two patients needed surgical decompression permitting pathological diagnosis. In the third case, osteonecrosis was ascertained by radiological evidence of an intravertebral vacuum phenomenon. Three etiologic factors were noticed: osteoporosis, corticotherapy, and radiotherapy. The relative frequency of neurologic complications in vertebral collapse related to osteonecrosis compared to those observed in osteoporosis is discussed.