Despite the critical importance of emergency exercises for emergency preparedness, there are major deficiencies in some organizations in managing their exercises. Lack of a comprehensive and systematic approach to emergency exercises can waste organizational resources and diminish the response confidence. The present study was conducted to identify and prioritize influencing success factors for planning, implementing, and improving the exercise process. In this study, a pattern for exercise management process was established based on relevant standards and guidelines. Then, the success and failure factors for each step of a typical exercise were identified based on previous studies. Finally, Fuzzy analytic hierarchy process was used to prioritize the identified influencing factors. Based on literature review and experts' opinions, 28 factors influence the success of emergency exercises. Although relative importance of all factors was close to each other, findings showed that "establishing the base of support for an exercise program," "designing the scenario," "presentations/briefings," "using expert evaluators," and "defining appropriate corrective actions plan" had the greatest impacts on the success of an emergency exercise.