Introduction – In France, occupational hearing loss was the fifth most commonly recognized occupational disease under the general social security system in 2022. From 1970 to 2000, the University Institute of Occupational Medicine in Lyon conducted audiometric screening campaigns in companies in the Rhône-Alpes region to assess the impact of noise pollution on workers’ hearing. The analysis of these data aims to evaluate the trend in average hearing loss among this population over this period. Materials and Methods – The database used contains 49,600 audiometric examinations. Selection criteria based on age, length of employment, and the absence of ear disorders were applied, and 8,270 audiograms were ultimately analyzed. An average hearing loss and its 95% confidence interval (95% CI) in dB were calculated based on the frequencies used for occupational disease reporting (500, 1,000, 2,000, and 4,000 Hz for both ears). The prevalence of hearing loss of at least 20 dB and of disabling hearing loss (≥35 dB) was also calculated based on the average audiometric loss for these same frequencies in the better ear. Average hearing losses and prevalence rates were calculated by sex, occupation (based on the 2003 classification of occupations and socio-professional categories), and economic sector (based on the 2008 French classification of economic activities) and broken down into three distinct periods: 1970–1979, 1980–1989, and 1990–2000. Results – The population consists mainly of men (85.1%) with a mean age of 39.2 years (95% CI: [39.0–39.4]) and an average length of service of 14.4 years [14.2–14.6]. Although the difference is statistically significant, the mean age and average length of service are similar across the three periods. There was a significant decrease in the average hearing loss among men during the study period, from 21.5 dB [21.1–21.9] in 1970–1979 to 14.5 dB [13.7–15.2] in 1990–2000. Between 1970 and 2000, one-third of men had hearing loss of at least 20 dB (34.4%), and the prevalence of disabling hearing loss (≥35 dB) was 6.1%. Conclusion – The analysis of audiometric measurements taken over a long historical period has documented the evolution of average hearing loss among several occupational groups of workers exposed to noise. The decline observed in this population should be viewed in conjunction with the measures implemented under French and European law since 1970 aimed at improving working conditions.