Although occupational musculoskeletal diseases are one of the most prevalent occupational diseases and cost billions of money, limited number of studies were conducted to develop the valid and reliable measure for ergonomic factors, the most important risk factors of these diseases. This study was conducted to develop a questionnaire for ergonomic factors and to evaluate the reliability of the developed questionnaire among foundry workers in Korea. A questionnaire for ergonomic factors was developed on the basis of the results of previously conducted studies and information obtained from a site visit of the worksite. The developed questionnaire was administered to 51 foundry workers at an interval of two weeks. The reliability of the questionnaire was evaluated using Cohen's Kappa, weighted Kappa, spearman's correlation coefficient and category distinguishability in the raw scale and dichotomized scale. The questionnaire items showing high Cohen's kappa include 'walking (0.79)', 'sitting(0.66)' 'raised elbow(0.65)', 'rotated elbow(0.64)', 'lifting(0.66)', 'push & pull(0.66)' and the items of low Cohen's kappa include 'one leg(0.31)', 'wrist lateral deviation(0.22)', 'palm padding(0.14)', 'pinch grip(0.15)'. It seems that the types of work, difficulty of recognition about the posture or movement, and understanding the questionnaire items affect the reliability coefficiencies.