The effects of fat levels on changes in flavor pattern of irradiated pork patties were evaluated by using electronic nose. Total peak amount decreased with increasing fat level and irradiation dose, and the increased fat level and irradiation dose influenced the formation of new peaks at latter retention time. For the principal component analysis, the irradiated pork patties with containing higher fat level were clearly separated from the other treatments. The irradiation dose also affected the position of spot in identical fat level. It is possible to distinguish the changes in flavor patterns due to fat content and irradiation dose by using electronic nose.