An investigation of the bone mineral density of lumbar vertebrae L1 to L3 with quantitative computed tomography was undertaken in 12 patients who had undergone hip rearthroplasty because of aseptic prosthetic loosening. The same measurements were carried out in a control group of 13 patients who had undergone hip arthroplasty, but not rearthroplasty. A good correlation was found between the cancellous bone mineral density in lumbar vertebrae L1 to L3 in each patient. In contrast to earlier findings of a post-traumatic effect on the appendicular skeleton after rearthroplasty, no significant difference was found in vertebral bone mineral density after the rearthroplasty.