OBJECTIVES: This study aimed to characterize trends in occupational noise-induced hearing loss (ONIHL) incidence, and to assess noise exposure levels and changes in audiometric thresholds among workers. METHODS: This retrospective study analyzed audiometric data from 72,952 workers between 1980 and 2019. Incidence rates of ONIHL were calculated. The first and last audiograms for each worker were compared, and noise exposure levels were analyzed. RESULTS: The final cohort included 36,984 workers. ONIHL incidence fluctuated between 4.0% and 7.0%, with a slight upward trend from 2000 to 2019. Noise exposure exceeded 85 dBA for 69.3% of workers with available measurements. Audiometric thresholds significantly worsened from the first to the last audiogram. CONCLUSION: Between 1980 and 2019, ONIHL incidence showed a slight increase. Ongoing monitoring of ONIHL trends and enhanced prevention initiatives are critical for mitigating future risks.