Recognizing the importance of occupational safety and health (K3) in order to provide a sense of security and prevent work accidents so as to increase morale or performance of other workers. The study discusses the effect of the application of occupational safety and health (K3) on the performance of construction project workers. Companies are requested to immediately apply the new Occupational Safety and Health (K3) standards as stated in the Minister of Manpower Regulation (Permenaker) No.5 of 2018 concerning K3. Employers and Management who do not meet the provisions in this Ministerial Regulation are subject to sanctions in accordance with the Law Number 1 of 1970 concerning Work Safety and Law Number 13 of 2003 concerning Employment. On this occasion the researchers used quantitative methods and the research was conducted at the Cijago Depok toll road during working hours. The average weighting value is 84%, so it can be said that the application of the safety management system and occupational health (SMK3) on the Cijago toll road section 2 B project has been running quite well and effectively. However, in this study, several variables have the lowest score and can affect project performance. Therefore, these variables will be given preventive variables including is variable which has a weight of <76%, namely: X13 which is a variable with the statement "The company presents the results of measurements of noise, vibration, temperature, dust to ensure the implementation of K3 is going well and correctly" therefore according to expert opinion there is a need for preventive measures. The variable that can affect project performance is the variable that has the highest weighting, X17 regarding "OHS regulations and procedures needed" with a weighting of 89% means that project performance is influenced by project workers who feel safe if there are OHS regulations and procedures required that are clearly described and as evidenced by the increase in the S curve