PT INKA (Persero) has 2 divisions in the production process, namely Fabrication and Finishing. In 2024, the number of work incidents in fabrication is 7 cases and finishing 2 cases. The work incident was an unsafe act in doing work. This is in line with the purpose of this study to analyze the relationship between workers' knowledge about occupational safety and health and unsafe actions among PT INKA workers. The design used in this study is observational analysis with a quantitative approach carried out from September 2024 to January 2025 at PT INKA Madiun. The object of this study is PT INKA's welding workers, which totals 38 people. Based on the results of this study, it can be concluded that the higher the knowledge, the lower the unsafe action or unsafe action by obtaining the results of the spearman rho rank correlation test, the result of rxy=-0.443 with a value of p=0.005 can be determined. Advice is given to conduct periodic supervision, inspection and evaluation of workers on occupational safety and health procedures and involve workers in the process of developing and implementing occupational safety and health policies.