Background Osteoporosis is a growing – yet preventable – public health issue, affecting more than 1 in 3 women. Costing the NHS an estimated £4.4 billion per year, early detection of low bone mineral density (BMD) and prevention of osteoporosis in mid-adulthood is considerably more effective than pharmaceutical intervention in later life. Failure to reach and maintain peak BMD during adulthood (e.g. by regular weight-bearing exercise) is a critical factor in determining future osteoporosis risk. Self-reported physical functional health, a measure determined by health and lifestyle factors such as physical activity, has previously been shown to predict health outcomes such as mortality and stroke risk. In this study, we seek to examine whether self-reported physical functional health may be predictive of future BMD. Methods The association between physical functional health and future BMD was investigated in participants aged 40-79 years enrolled in the European Prospective Investigation of Cancer-Norfolk study. Associations between a participant’s SF-36 physical component summary (PCS) score, measured 18 months after baseline health check, and broadband ultrasound attenuation (BUA – a measure of BMD), measured 2-5 years after baseline, were examined using sex-specific multivariate linear and logistic regression analyses adjusting for age, BMI, medical co-morbidities, lifestyle and socioeconomic factors. Results Complete data from 10,203 participants (57.1% female), mean (SD) age 61.5 (8.9) years were analysed. Low PCS score was associated with a reduced BMD; in the linear regression analysis, for every one unit decrease in PCS score in men and women, there was a 0.1 dB/MHz (p<0.001) decrease in mean BUA. In logistic regression analysis, low PCS score (less than one standard deviation (1 SD) below the sex-specific mean) was associated with having a poor BUA value (less than 1 SD below sex-specific mean), which is indicative of osteopenia. Results were highly significant in women [odds ratio (95% confidence interval) 1.527 (1.263, 1.847); p<0.001], but lesser so in men [odds ratio (95% confidence interval) 1.406 (0.991, 1.994); p=0.056]. Furthermore, low PCS score was also shown to predictive of very low BUA (less than 2.5 SD below sex-specific mean) in women, which is indicative of osteoporosis [odds ratio (95% confidence interval) 5.960 (2.084, 17.049); p<0.001], although findings were less significant in men [odds ratio (95% confidence interval) 2.823 (0.966, 8.255); p=0.058].  Conclusion Study findings indicate that self-reported physical functioning is a tool capable of predicting future BMD and identifying at risk individuals in an apparently healthy population, especially in women. In the current climate, where increased sedentary activity and a reduction of routine medical appointments will have implications on bone health, self-reported functional health may prove a useful and inexpensive indicator to stratify populations by risk of low BMD. Future research is needed to examine the clinical applications of self-reported physical functioning scores and its capability to identify poor BMD before further decline.