Abstract : The oil and gas industry deals with hazardous materials, uses high-risk processes, still uses a lot of manpower, and uses large and complex equipment facilities construction. Therefore, the implementation of occupational health and safety is needed in the oil and gas industry. In this study, the development of a CBA model for the implementation of occupational safety and health will be carried out in oil and gas contractors in Indonesia by exploring the relationship between prevention costs and benefits. The aim is to see the side of the economic impact on the effective / ineffective OHS management by oil and gas contractors. This research uses quantitative and qualitative approaches. The analysis is based on these quantitative numbers. The results show that the existence of an evaluation analysis of the benefits of implementing OHS based on an economic perspective that has a significant relationship in improving working conditions is a profitable investment. Cost benefit analysis can be used as a parameter in making decisions related to occupational health and safety implementation. With the OHS CBA model, the contractor can predict the amount of cost that is issued to benefit from the implementation of occupational health and safety.