The self-reported prevalence of, and attitudes to and perceptions of, osteoporosis in the South Australian community were assessed using data collected as part of the 1995 South Australian Health Omnibus Survey (household interviews)--a clustered, self-weighting, multistage sample of households in metropolitan and country centers. The self-reported prevalence was 4.8 (95% CI: 3.7-5.8) and 1.4% (95% CI: 0.8-2.0) for women (n = 1531) and men (n = 1485) respectively. For individuals with osteoporosis, calcium was the favored treatment (52%), while 33% of women were on hormone replacement therapy. An appropriate definition of osteoporosis was given by 62% of women and 37% of men. The main risk factors were reported as lack of calcium and age. There was a significant association between knowledge of the definition of osteoporosis and identification of correct risk factors. A high perceived risk of osteoporosis was reported in 23% of women and 7% of men. Osteoporosis risk was assessed as higher in those who did not adopt recognized prevention measures. Perception of risk was not related to the individual's own risk factors. Self-reported prevalence of osteoporosis significantly underestimates the likely true prevalence and general awareness and knowledge is much lower for men than women. The importance of individual risk factors for osteoporosis are not understood by the general community.