Objectives To investigate the association between hearing loss, hearing aid use, and cognitive decline. Design Prospective population‐based study. Setting Data gathered from the Personnes Agées QUID study, a cohort study begun in 1989–90. Participants Individuals aged 65 and older (N = 3,670). Measurements At baseline, hearing loss was determined using a questionnaire assessing self‐perceived hearing loss; 137 subjects reported major hearing loss, 1,139 reported moderate problems (difficulty following the conversation when several persons talk at the same time or in a noisy background), and 2,394 reported no hearing trouble. Cognitive decline was measured using the Mini‐Mental State Examination (MMSE), administered at follow‐up visits over 25 years. Results Self‐reported hearing loss was significantly associated with lower baseline MMSE score (β = −0.69, P < .001) and greater decline during the 25‐year follow‐up period (β = −0.04, P = .01) independent of age, sex, and education. A difference in the rate of change in MMSE score over the 25‐year follow‐up was observed between participants with hearing loss not using hearing aids and controls (β = −0.06, P < .001). In contrast, subjects with hearing loss using a hearing aid had no difference in cognitive decline (β = 0.07, P = .08) from controls. Conclusion Self‐reported hearing loss is associated with accelerated cognitive decline in older adults; hearing aid use attenuates such decline.