All Australian Commonwealth annual reports presented to the Federal Parliament are mandated to include both an alphabetical index and a list of requirements to aid access. The authors analysed all 175 Commonwealth government department and agency annual reports produced for the 2016–17 financial year to see how well they met the aids-to-access and devised usability criteria. This investigation examined the alphabetical indexes, specifically areas around layout, quality of indexing, depth of indexing and indexing style. Two-thirds of the Commonwealth annual-report indexes were deemed satisfactory. A checklist was also developed for departments and agencies to check the usability of the alphabetical index in their annual reports.