The growing demand for medications to treat or prevent osteoporosis is one reason for the rapid development of drugs in the bisphosphonate class. Researchers and clinicians are enthusiastic because each new generation of bisphosphonates has shown increased efficacy and greater convenience in administration compared with predecessors. At the 24th Annual Meeting of the American Society for Bone and Mineral Research (ASBMR) [San Antonio, US; September 2002], considerable attention was devoted to bisphosphonates, including the presentation of results of the first head-to-head study comparing the efficacy of alendronic acid ['Fosamax'] and risedronic acid ['Actonel'] for the treatment of postmenopausal osteoporosis. Although both treatments were effective, weekly administration of alendronic acid provided significantly greater reductions in bone resorption, and larger increases in spine and hip bone mineral density (BMD), compared with daily doses of risedronic acid. In a separate study, the longest conducted with a nonhormonal osteoporosis therapy to date, alendronic acid was shown to provide continued improvements in bone mineral density over a 10-year period.