BACKGROUND: With the rapid increase in the elderly population and the ensuing increase in osteoporosis and subsequent fractures, there has been a rise in socioeconomic costs. This study evaluated the relationship between osteoporosis and physical function in 66-year-old Korean women. METHODS: All of the 193 Korean women aged 66 years were recruited from life-transition health examinations from May to December, 2007. Background information was collected through a self-administered questionnaire; and height, weight, and waist circumference were measured. Bone mineral density of the lumbar spine was measured with the Dual Energy X-ray Absorptiometry and the 'timed up and go (TUG)' and 'one-leg balance (OLB)' tests were administered. Risk factors for osteoporosis were analyzed by correlation coefficients and binary logistic regression analysis. RESULTS: The prevalence of osteoporosis for 66-year-old women was 25.9%. A short stature and lower body mass index (BMI) were associated with osteoporosis of the lumbar spine. A longer time to complete the TUG test (>10 second) was associated with a 4-time higher prevalence of lumbar osteoporosis, which was not observed with the OLB test. CONCLUSIONS: One out of four 66-year-old Korean women had osteoporosis. A longer TUG time, short stature, and lower BMI were associated with osteoporosis.