In the agIng population, osteoporosis is an important public health problem worldwide due to its high morbidity and mortality. Also, metabolic syndrome (MS) is another very common medical problem of epidemic importance, and the number of patients with MS is rapidly increasing in industrialized countries.There have been many studies about the relationship between MS and bone metabolism, but their results are inconsistent. A population-based US study has shown that bone mineral density (BMD) of the femoral neck Association between bone mineral density and metabolic syndrome in pre-and postmenopausal women We measured BMD at the lumbar spine and femoral neck. MS was defined according to the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) criteria. The prevalence of MS was 5.5% in the premenopausal group and 13.5% in the postmenopausal group. In the postmenopausal group, C-reactive protein (CRP) was significantly higher in subjects with MS than those without MS, but it was not in the premenopausal group. In the postmenopausal group, women with MS had a lower BMD at the lumbar spine and femoral neck before or after adjustment. In the premenopausal group, women with MS had a lower BMD at the lumbar spine, but not at the femoral neck. In stepwise linear regression analysis, predictive variables for BMD of the lumbar spine were systolic blood pressure in the premenopausal group and HDL-cholesterol and diastolic blood pressure (DBP) in the postmenopausal group. The predictive variables for BMD of the femoral neck were DBP and waist circumference in the premenopausal group and CRP and DBP in the postmenopausal group. Inflammation might have a more important role in BMD than obesity in the postmenopausal women.Key words: Bone mineral density, Metabolic syndrome, Menopause increases with increasing components of MS [1]. On the other hand, men with MS had a lower BMD after adjustment for body mass index (BMI) in the Rancho Bernardo Study [2] and women with MS also have a lower BMD in a recent study [3]. A prospective study has also demonstrated that men with MS had a lower BMD at the hip, whole body and distal forearm [4]. MS is characterized by abdominal obesity, impaired glucose tolerance, hypertension and dyslipidemia [5]. MS is a cluster of conditions with detrimental effects on cardiovascular health and has a strong association with low grade inflammation [6]. Obesity or high BMI is known to be a protecting factor against excessive bone loss in aging [7][8][9][10]. However, inflammation is more severe in subjects with high insulin resistance than in those with low insulin resistance [11,12], even-