Importance Although hearing loss is common in the population worldwide, the prevalence of hearing loss and hearing aid use is not known. Objective To estimate the prevalence of hearing loss and hearing aid use in the adult French population. Design, Setting, and Participants This cohort study used data from the CONSTANCES cohort, a representative sample of the French population. Volunteers aged 18 to 75 years were recruited at 21 preventive health centers between January 1, 2012, and December 31, 2019. The present study included participants with audiometric data. Main Outcomes and Measures The main outcomes were prevalence of hearing loss and disabling hearing loss overall and by sex and age group and prevalence of self-reported hearing aid use among those with disabling hearing loss. Hearing loss was defined as a pure-tone average (PTA) in the better ear of 20 dB or higher, and disabling hearing loss was defined as a PTA in the better ear of 35 dB or higher. Results Of 200 870 participants in the CONSTANCES study, 186 460 had full audiometric data and were included in this study (mean [SD] age, 47.1 [13.5] years); 100 330 (53.8%) were female, and 86 130 (46.2%) were male. Of these participants, 24.8% (95% CI, 24.6%-25.0%) had hearing loss and 4.3% (95% CI, 4.2%-4.4%) had disabling hearing loss. The prevalence rates of hearing loss increased from 3.4% (95% CI, 2.8%-3.9%) at age 18 to 25 years to 73.3% (95% CI, 69.5%-77.2%) at age 71 to 75 years among men and from 4.4% (95% CI, 3.9%-5.0%) at age 18 to 25 years to 64.1% (95% CI, 59.7%-68.4%) at age 71 to 75 years among women. The prevalence of disabling hearing loss increased from 0.3% (95% CI, 0.2%-0.4%) among participants aged 18 to 25 years to 23.3% (95% CI, 20.7%-26.0%) among participants aged 71 to 75 years. Among the 8050 participants with disabling hearing loss, 36.8% (95% CI, 35.8%-37.9%) reported using hearing aids, including 56.7% (95% CI, 38.9%-74.4%) aged 18 to 25 years and 32.9% (95% CI, 26.8%-39.2%) aged 71 to 75 years. Conclusions and Relevance In this cohort study, hearing loss was prevalent in France, and the prevalence of hearing loss increased with age among both men and women. Hearing aids were underused, particularly among older individuals. These findings suggest that hearing loss prevention and screening in the French population are needed.