Introduction: There is limited evidence on the cost-effectiveness of joint replacement registries. This study investigates two key questions: (i) Has the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) been cost-effective in improving the health outcomes of Australian joint replacement recipients? and (ii) Do the benefits of the registry outweigh its costs? Materials and methods: A cost-utility and a cost-benefit analysis was performed from the healthcare system perspective, with a secondary analysis from the payer’s perspective. Participants were patients who underwent hip or knee replacements between July 1999 – December 2021. Health outcomes, measured as Quality-Adjusted Life Years (QALYs), revisions averted, and recalled prostheses, were converted to monetary terms using the value of a statistical life year, revision costs and protheses costs. Costs were presented in 2022 Australian dollars, with a discount rate 5% per annum. Decision-making thresholds were set at a willingness-to-pay of AU$50,000/QALYandabenefit-costratioof1.Results:Fromthehealthcaresystemperspective,theincrementalcost-effectivenessratio(ICER)wasdominant(cheaperandprovidesbetteroutcomes)(AU$-170,982/QALY), with a benefit-cost ratio of 10.29. From the payer’s perspective, the ICER was also dominant (AU$-60,137/QALY) with a benefit-cost ratio of 10.49. Results remained robust across sensitivity analyses. Conclusion: The AOANJRR is highly cost-effective, demonstrating significant health and financial benefits. For every dollar spent by the government, approximately nine dollars were saved. Verifying the cost benefits of clinical quality registries is crucial to justify ongoing investments, support informed clinical decisions, and ensure high-quality, accurate data for continuous improvements in patient care and safety.