Complementary and alternative medicine (CAM) therapies have become increasingly popular and are used regularly by patients with osteoporosis in Australasia and worldwide. This study was done to determine the prevalence and patterns of use of CAM in an Australian osteoporosis clinic. This was a prospective, cross-sectional questionnaire-based study of 202 patients attending an academic osteoporosis clinic in Sydney, Australia. Subject had a mean age of 68.5 +/- 10.9 years, 79.7% were female, and 55.9% were born overseas. CAM use was reported by 104 patients (51.5%) using the standard and 62 patients (30.7%) using the stringent definition of CAM. The most frequent CAM were multivitamins (24.0%), acupuncture (19.2%), t’ai chi (14.4%), and yoga (12.5%). Seventy-three percent (73%) did not consult a physician before starting CAM and 23.1% stated that their treating specialists were unaware of CAM use. The most common reasons for using CAM were having a holistic approach (53.0%) and inadequate pain control (29.0%). CAM users were associated with Asian country of birth (23.1% versus 12.2%, p = 0.03), more frequent clinic visits over a 12-month period (1.8 versus 1.5 times, p = 0.03), and a trend for a worse lumbar spine T-score (-2.35 versus -2.20 SD, p = 0.05) and higher rates of university education (26.0% versus 14.3%, p = 0.05). It is estimated that $696 million is spent annually on CAM by patients with osteoporosis. Patients attending osteoporosis clinics frequently use CAM. Physicians may need to routinely inquire about a history of CAM use to ensure better screening for possible adverse clinical interactions.