Objective: It is well known that firefighters face serious risk to their health and safety in the performance of their duties. To determine whether individuals who work as firefighters sustain occupational noise-induced hearing losses, we evaluated results of hearing tests completed by firefighters and compared them with age-matched, non-occupationally exposed groups of individuals. Design: The results of annual audiometric testing and a related questionnaire collected as part of a company-wide hearing conservation program were obtained from two large urban fire departments. The records from 12,609 tests conducted over an 11-year period were evaluated. Hearing levels obtained from the tests were compared with age-matched control populations from an American national standard, and a longitudinal study comparing the rate of hearing loss to that expected due to presbycusis alone was conducted. Results: Comparisons of the data to the national standard indicated that firefighters do not exhibit excessive loss of hearing compared with age-matched, non-occupationally exposed control subjects. The longitudinal study that examined the regression of firefighters' hearing with age compared with the expected presbycasic regression function indicated that the hearing of firefighters in the study declined over the 7-year period at a rate that was less than that expected due to age alone. Conclusions: The results of this large-scale, cross-sectional, and longitudinal study indicate that firefighters are not at risk for occupational noise-induced hearing loss, even though they work nonstandard shifts and are occasionally exposed to high levels of noise. The results are consistent with the findings but not the conclusions of several other studies of firefighters' hearing.