 We propose a pilot randomized controlled trial to assess the efficacy and feasibility of Tai Chi as an adjunct to standard care for post-menopausal osteopenic women. Eight-six osteopenic women ages 45-70 will be recruited from a large multi-specialty group practice. Our primary aim is to assess the feasibility for recruiting and retaining osteopenic women into a randomized controlled trial of 9 months of Tai Chi. Our secondary aim is to collect preliminary data on the efficacy of Tai Chi in reducing rates of bone loss in osteopenic women using sensitive markers of bone turnover and dual-energy x-ray absorptiometry. The results of this study will inform the design of a future trial evaluating the benefits and safety for Tai Chi for osteopenic women, as well as the physiological and biomechanical mechanisms through which Tai Chi may impact BMD and fracture risks associated with osteopenia. 