This 2 arm study will assess the impact of Bone Marker Feedback (BMF), using blood sampling and communication of the results at 2 months, on adherence to monthly Bonviva (150mg po) in women with post-menopausal osteoporosis. Patients will be randomized into either 1) a group which receives bone marker feedback or 2)a group which does not receive feedback on the results. The study will also assess patient satisfaction with treatment with once monthly Bonviva. The anticipated time on study treatment is 3-12 months, and the target sample size is 500+ individuals.