The Osteoporosis Self-assessment Tool for Asians (OSTA) was developed to help physicians focus their efforts on patients at increased risk, and encourage appropriate use of bone mineral density (BMD) measurements. Previously, OSTA performed well in a sample of women from eight countries in Asia, and in a validation group of Japanese women. In this study, we evaluate the performance of OSTA using a sample of 1101 postmenopausal women from a clinic in Korea who had femoral neck BMD measurements by dual-energy X-ray absorptiometry (DXA). The OSTA had a high sensitivity (87%), and good specificity (67%) for identifying osteoporosis (BMD T-scores <or= -2.5); the corresponding values were 80% and 72% for identifying T-scores <or= -2.0. The prevalence of osteoporosis ranged from 2% among women classified as low risk (OSTA > -1) to 64% among those classified as high risk (OSTA < -4); these results were almost identical to those reported earlier for a sample of women from eight Asian countries. We conclude that the OSTA risk tool performed well in this sample of postmenopausal Korean women, similar to previous results in other Asian women. The OSTA tool is free and very easy to use; risk can be tabulated by age and weight, so that calculations are not necessary. Using OSTA could encourage patients and clinicians to actively assess osteoporosis, and measure BMD when appropriate, before fractures occur.