This study investigated the client's duty and role to prevent construction accidents by participating construction client into the occupational safety and health management system. Since the fatal accidents of the construction sites in Korea are higher than other OECD countries and approximately 500 workers annually have died on construction sites, various efforts have been performed to prevent construction accidents. Recently, in Korea, the client’s participation in the safety and health management system has been focused as a fundamental method to prevent serious accidents. To examine the necessity of client’s participation, the survey was performed for construction participants. And, survey results and existing studies about client's role were analyzed to assign responsibility and role to the client. Results showed that safety managers and supervisors were strongly agreed for imposing client's duty (average scores of 4.373 and 4.107 in likert 5point scale) while clients showed the lowest agreement (average score of 3.153). In addition, the detailed role was proposed in the whole project stage, that is plan, design, and construction stage. Client can be a key player in reducing the fatal construction accidents by doing the accurate roles proposed in this study.