This 2 arm study will assess the impact of bone marker feedback, using blood sampling and communication of results at week 5, on persistence to monthly Bonviva (150mg po) in women with post-menopausal osteoporosis. The study will also assess safety, quality of life and patient satisfaction. All patients will receive Bonviva 150mg po monthly, and will be randomized into the bio-feedback or no bio-feedback study arms. The anticipated time on study treatment is 3-12 months, and the target sample size is 500+ individuals.