To study bone involvement in primary biliary cirrhosis (PBC), we used dual-energy X-ray absorptiometry to measure bone mineral density (BMD) in Japanese women with PBC and with cirhosis of the liver. In both groups, in each decade up to 60 years of age, the mean BMD of the lumbar spine was not significantly different from that in healthy Japanese women; however, in patients aged 60 years or more, the level was significantly lower both in the patients with PBC (P<0.001) and in those with cirrhosis of the liver (P<0.01). Patients with PBC were also examined by single-photon absorptiometry. The BMD of the radius in the patients with PBC was less changed than that of the lumbar vertebrae; thus, the bone changes in PBC seem to be greater in spongy than in cortical bone.