Grain dust is the dust produced during harvesting, drying, handling, storage or processing of wheat, oats, rice, barley or maize. Grain dust is composed of a large number of materials including various types of grain and their disintegration products, silica, fungi, insects and mites. The study aims to assess the knowledge and determine the relationship regarding the ill effects of grain dust exposure on respiratory system among flour mill workers. The research approach for this study is explorative and descriptive survey. The researcher planned to explore the knowledge regarding the ill effects of grain dust exposure on respiratory system and its prevention. The structured interview schedules were tried out with flour mill workers in selected flour mill at Bangalore rural. Split half method was done and co- efficient correlation was found (r= 0.82) which indicates high degree of reliability. Finding of the study showed, knowledge score of the flour mill workers 82% of them were having below average knowledge and 10% of them were having average knowledge and 8% of them only having good knowledge regarding the ill effects of grain dust exposure. The study concluded that the knowledge of mill workers is a basic education programme in community area such as occupational health. The primary task of nursing education is to improve the knowledge and practices to prevent the ill effects among occupational development among the community.