BACKGROUND: Data on work-related ill-health (WRIH) in the Republic of Ireland is inconsistent. AIMS: To compare the incidence of WRIH in the Republic of Ireland (ROI), Northern Ireland (NI) and Great Britain (GB) reported by clinical specialists in skin and respiratory medicine and by specialist occupational physicians (OPs). METHODS: Analysis of data reported to three surveillance schemes in The Health and Occupation Research (THOR) network in ROI and corresponding UK schemes. RESULTS: Contact dermatitis was the most frequently reported skin disease in the three areas. Asthma was the most frequently-reported respiratory disease in the ROI, while asbestos-related cases predominate in GB and NI. Mental health disorders, followed by musculoskeletal disorders were reported most frequently by OPs. Annual average incidence rates for skin disease were 2 per 100000 employed (95% confidence interval [CI] 1.9-2.8) in the ROI and 7 per 100000 for GB (95% CI 4.8-9.4). Unadjusted incidence rates for respiratory disease were 1 (95% CI 0.3-1) and 8 (95% CI 6.1-10.7) per 100000 in the ROI and GB, respectively; adjusted for reporter non-response, these figures increased to 15 (95% CI 11.3-19.6) and 32 (95% CI 28.4-35.6) per 100000 respectively. CONCLUSIONS: This is the first paper to include THOR data on WRIH from the ROI, NI and GB. Consistent and dedicated data collection in the ROI via the THOR schemes is viable and important in the light of a deficit of occupational ill-health data. Sustained efforts to improve participation are underway.