AIMS: The efficacy of treatments for osteoporosis can be evaluated using a variety of study designs. This article aims to comprehensively review the evidence for bisphosphonate anti-fracture efficacy in postmenopausal women, discussing the strengths and limitations associated with each study method. METHODS: Literature analysis included English-language publications reporting results of randomised controlled trials (RCTs), post hoc analyses, meta analyses and observational studies evaluating the efficacy of alendronate (ALN), ibandronate (IBN), risedronate (RIS) and zoledronate (ZOL), with an initial sample size ≥ 100 patients, and follow-up data for at least 1 year. RESULTS: Primary and secondary analyses of RCT data suggest differences among bisphosphonates with regard to site-specific anti-fracture efficacy and onset of fracture risk reduction. While some observational studies indicate differences in clinical outcomes among these agents, others report similar effectiveness. ALN and RIS data demonstrate sustained fracture protection for up to 10 and 7 years of treatment respectively. The efficacy of IBN and ZOL has been evaluated for up to 3 and 5 years respectively. CONCLUSIONS: Understanding of the benefits of bisphosphonate treatment can be maximised by evaluating complementary data from RCTs and observational database studies. Fracture risk reduction with bisphosphonates is shown in RCTs and in real-world clinical settings.