Abstract: Objective The effectiveness of control measures against occupational hazards in a COREX project was comprehensively evaluated using fuzzy mathematics method. Methods Control measures against occupational hazards in this project were surveyed by the on-site inspection. The level of occupational hazards, including chemical agents, dust and noise,at various workplaces were determined. The fuzzy matrix and weighting coefficient for these hazards was assigned, considering the hazard severity, the concentration or intensity of hazards and the number of workers exposed to hazards in each workplace (evaluation unit). The total score was calculated to indicate the effectiveness of control measures. Results According to COREX procedures, the workplaces can be divided into 3 characteristic areas (evaluation units), namely raw material feeding unit,iron smelting unit and wastewater treatment unit. The effectiveness of control measures against occupational hazards in each unit was ranked as Grade 2 (good). The comprehensive evaluation for whole project was also ranked as grade 2. Conclusion The fuzzy mathematics model is useful to evaluate comprehensively the effectiveness of control measures, since in this model the multiple factors, such as the characteristics and levels of occupational hazards and the number of exposed workers, were considered in qualitative or quantitative manner.