OBJECTIVES: The surveillance of noise-induced hearing loss (NIHL) according to the Health and Safety Executive (HSE) differs from the medico-legal criteria used to assess NIHL. Our study compares the two systems and proposes a novel method of simplifying the medico-legal criteria and applying it to ascertain noise-induced hearing loss. DESIGN: The anonymised audiograms of a group of 87 industrial workers from a single site were analysed with both methods. RESULTS: The comparison showed approximately one-third of the workers assessed in this study had their noise-induced hearing loss underestimated by the HSE criteria. The majority of these individuals were over 40 years of age. CONCLUSIONS: The HSE criteria for noise-induced hearing loss need review and re-alignment with the medico-legal criteria to address the discrepancy between the two systems.