The HAEA Emergency Response Organization (ERO) held a nuclear emergency exercise on November 3, 2005. The emergency response organization of the Paks NPP, as the “host” organization for the emergency, and the emergency centre of the National Directorate General for Disaster Management also participated in the exercise. The primary goal was to practice the implementation of the activities determined in the emergency preparedness provisions. Emphasized issue was to improve the cooperation between the participating organizations in the evaluation of the conditions of the damaged facility and in the determination of the consequences resulting from the released isotopes during the simulated accident and protective actions to be implemented. During the preliminary evaluation of the exercise, the members of the ERO and the designated evaluator stated the success of the exercise, and specified certain areas that should be further improved.