The neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) are known to be markers of the systemic inflammatory response. However, the few studies that have been done on the relationship between the NLR and PLR and osteoporosis have yielded inconsistent results. Therefore, we assessed the relationship between the NLR and PLR and bone mineral density (BMD). This study was conducted with postmenopausal patients admitted to an orthopaedic hospital. Data including BMD, NLR, PLR and covariates were obtained from the subjects’ medical records. In total, 407 postmenopausal patients were enrolled in this study. Analysis of covariance was performed to identify significant differences in BMD according to NLR and PLR. After adjusting for other covariates, a quartile of NLR was negatively associated with the mean value of lumbar BMD (p=0.040, p for trend=0.005) but not with the mean value of femur neck BMD. However, there were no significant associations among the PLR, the BMD of the lumbar and the femur neck. In conclusion, the quartile of NLR was negatively associated with the mean value of lumbar BMD in Korean postmenopausal patients.