<em>According to the World Health Organization (WHO) in 2014, 8% of many countries experience work-related illness, namely depression. Based on the results of the interview, it is known that there is an increase in workload due to vacancies in several departments so tha the workload must be delegated to existing employees. Field employee working hours are longer than office employees, from 7am to 5.30 pm. Based on the interview, the assignment and instructions were not given directly because the location was far enough to cause confusion among employees. In interviews, it was also shown that the majority of employees Performance Management System </em>(PMS)<em> did not change and even decreased more than the increase. This study aims to determine and analyze the effect of Work Overload, Role Ambiguity, and Organizational Culture on Job Stress.</em> <em>The population of this study were field employees of Badan Operasi Bersama (BOB) PT. Bumi Siak Pusako-Pertamina Hulu.The sample was calculated using the Slovin sampling technique, samples are 104 respondents. Furthermore, the sample is taken rendomly and based on the department using cluster sampling technique. The analytical method used in this research includes staistical descriptive analysis and quantitative analysis. The results of this study indicate that there is a significant positive effect of Work Overload on Job Stress, there is a significant positive effect of Role Ambiguity on Job Stress, and there is a significant negative effect of Organizational Culture on Job Stress. It os hoped that the company can improve the division of work hours among field employees.</em>