OBJECTIVES: There are few epidemiological surveys that have examined age-related hearing loss in an older Australian population. This study reports the prevalence, 5-yr incidence, and progression of hearing impairment in a representative sample of older persons. DESIGN: The Blue Mountains Hearing Study (BMHS) is a population-based survey of age-related hearing loss conducted among participants of the Blue Mountains Eye Study cohort. During the period 1997-1999, 2956 had audiometric testing done. Of these, 870 participants without hearing loss and 439 with hearing loss were re-examined from 2002 to 2004. RESULTS: Some degree of hearing loss was present in 33.0% of this population at baseline. Prevalence of hearing loss increased with age, sex-adjusted (odds ratio [OR] 3.5, 95% confidence interval [CI] 3.1-3.9), with men 70% more likely than women to have hearing loss. The 5-yr incidence of hearing impairment was 17.9%. For each decade of age older than 60 yrs, the risk of hearing loss increased threefold, OR 3.9 (CI 2.3-3.8). Gender was not associated with incident hearing loss OR. However, high occupational prestige was associated with decreased incidence of hearing loss OR 0.6 (CI 0.40-0.94). The 5-yr progression of hearing loss defined as a difference in pure-tone average that exceeded 10 dB was relatively high (15.7%). At the baseline hearing study and at the 5-yr follow-up hearing study, 57.4% and 59.7% of hearing impaired subjects, respectively, reported using a hearing aid for a maximum of 5 yrs. CONCLUSIONS: Hearing loss was a frequent sensory disability, with one in three persons having a hearing impairment, and of these, almost one in two showing a decline in hearing over a 5-yr period. This information can potentially contribute to the planning and resource investment in auditory rehabilitation services for older Australians.