Computed tomography (CT) provides precise anatomic localization coupled with quantitative x-ray attenuation information that can be used to determine bone mineral content. A precise and sensitive method for vertebral mineral measurement by CT is described and illustrated with results from an ongoing study of mineral loss in oophorectomized women. Spinal mineral loss measured by quantitative CT is compared with peripheral loss determined by photon absorptiometry and radiogrammetry. Vertebral cancellous bone loss was significant for the group as a whole at 12 months, while mean peripheral measurements showed no change. In two subjects in whom mineral change was significant at both sites, spinal loss was approximately five times greater than peripheral loss.