Objectives: To assess the costs of hospital accreditation in Australia. Design: Mixed methods design incorporating: stakeholder analysis; survey design and implementation; activity-based costs analysis; and expert panel review. Setting: Acute care hospitals accredited by the Australian Council for Health Care Standards. Participants: Six acute public hospitals across four States. Results: Accreditation costs varied from 0.03% to 0.60% of total hospital operating costs per year, averaged across the 4-year accreditation cycle. Relatively higher costs were associated with the surveys years and with smaller facilities. At a national level these costs translate to $A36.83 million, equivalent to 0.1% of acute public hospital recurrent expenditure in the 2012 fiscal year. Conclusions: This is the first time accreditation costs have been independently evaluated across a wide range of hospitals and highlights the additional cost burden for smaller facilities. A better understanding of the costs allows policymakers to assess alternative accreditation and other quality improvement strategies, and understand their impact across a range of facilities. This methodology can be adapted to assess international accreditation programmes.