Osteoporosis and increased carotid intima-media thickness (IMT) have been associated with atherosclerosis. We investigated the correlation between carotid IMT and lumbar spine bone mineral density (BMD) in postmenopausal women. We studied the carotid IMT in 175 postmenopausal women, including 43 women (control) with normal spinal BMD, 73 women with osteopenia, and 59 women with osteoporosis. Carotid IMT was assessed by ultrasonography. BMD at the lumbar spine (lumbar 2 to 4 vertebrae) was measured by dual-energy X-ray absorptiometry. Age, years since menopause, and carotid IMT were significantly greater in the osteoporosis group than in the control (all p<0.01) and osteopenia groups (all p<0.01). Estradiol was significantly lower in the osteoporosis group than in the control group (p<0.05). BMD was significantly lower in the osteoporosis group than in the osteopenia or control group (both p<0.01) and in the osteopenia group than in the control group (p<0.01). After adjusting for age, years since menopause, and estradiol, women with osteoporosis had significantly greater carotid IMT than controls (p<0.05). The univariate linear regression analysis revealed that carotid IMT was significantly positively correlated with age, years since menopause, and low-density lipoprotein (LDL) cholesterol (all p<0.05) and was significantly negatively correlated with estradiol and BMD (all p<0.05), but showed no significant association with other clinical variables. In multivariate regression analysis, the carotid IMT was significantly positively correlated with LDL cholesterol (p<0.01) and negatively correlated with BMD (p<0.01), but not with other variables. Carotid atherosclerosis might be associated with lumbar spine bone mass in postmenopausal women, suggesting that postmenopausal women with osteoporosis may have more advanced carotid atherosclerosis than those with a normal bone mass.