The purpose of this study is to identify the effects of emergency medical technicians' personal traits and job characteristics on job/social stress, job satisfaction, role conflicts, organizational commitment, and self-efficacy. The study population was emergency medical technicians who is working at the hospitals in Yeungnam province. The 200 questionnaires were administered by using ground mail, e-mail, and personal visits and 156 questionnaires were returned(82.5% response rate). Social stress, job satisfaction and role conflicts were significantly determined by personal traits and job characteristic variables. However, job stress, organizational commitment and self-efficacy was only significantly determined by job characteristic variables. In social stress and role conflicts, the subjects with challenge, sociability, acceptance and prudence traits were tend to be significantly higher scores compared to the stability traits. Additionally, among social stress regression models, adding job characteristics to the personal traits model, $R^2$ was increased up to 19% and adding personal traits to the job characteristics model, $R^2$ was increased up to 14%. In conclusion, the study found that personal traits and job characteristics are important variables in explaining social stress, job satisfaction and role conflicts, that would have important managerial implications for recruiting, hiring and managing either new or current emergency medical technicians efficiently.