The present paper aims at identifying and ranking the factors affecting job stress of HSE employees in the phase 14 of the South Pars (a petroleum company in south of Iran). In this cross sectional study, all HSE employees in one of the phases in south pars of Iran (the phase 14) including 150 employees were investigated in 2015. The data were collected using a questionnaire and measuring some environmental and occupational factors such as sound and chemical pollution. The validity of the questionnaire was approved by opinion of the 10 expert persons in this field (Content Validity Index .85%) and the reliability of the questionnaire was approved by Cronbach Alpha equal to 0.70. At present study the one sample T test indicated that the environmental and managerial factors affect job stress of the HSE employees. Among the environmental factors, long working hours, poisonous materials risks, air pollution, heat and moisture and air pollution mostly affect job stress, respectively. On the other hand among the managerial factors, job security, lack of meritocracy, not in time payment and prejudice in salary affect job stress the most, respectively. As the results of this study, respect to environmental and occupational factors according to employees’ viewpoint in each industry is too important.