Objectives: To identify work stress and affecting factors of the emergency medical technicians(EMT) and to provide basic data for work circumstance improvement and emergency medical service and duty efficiency elevation. Methods: The data were collected by questionnaire from 635 emergency medical technicians throughout the whole country from August 5 to September 20 2013 and analyzed by using the SPSS(version 18.0) program. Factors affecting stress were analyzed by Multiple Linear Regression Analysis(${alpha}=0.05$). Results: Mean level of job stress was markedly high in the spot situation(3.43 point), user awareness(3.31 point), burden related to work(3.21 point), role and conflict as a professional job(3.10 point), unsuitable treatment(2.95 point) but was lowest in specialty demand of knowledge and skill(2.76 point). Conclusions: To diminish work stress, understanding and cooperation of the residents and reduction of burden related to work must be improved. Above all, positive interest of 119 and related organ and duty environment improvement will and effort and continuous measure establishment and support and cooperation of the government are needed.