Forecasting demand for mega-events is prerequisite for event managers since accurate demand is necessary to determine supply for mega-events. In this respect, the purpose of this study is to compare three types of forecasting methods when predicting demand for Expo visitors. These forecasting methods include 1) forecasts with willingness-to-visit(WTV), 2) forecasts with WTV+Gruber index, and 3) forecasts with WTV+Self-confidence index. The last two methods reflect feasibility rate. To this end national surveys were conducted to residents of 16 metropolitan cities and provinces using telephone and internet surveys. The results indicate that approximately 25 million Expo visitors were predicted by method 1(forecasts with WTV only), 10 million visitors were predicted by method 2(forecasts with WTV+Gruber index), and 18 million visitors were predicted by method 3(forecasts with WTV+Self-confidence index). The findings imply that forecasts with willingness-to-visit only overestimated Expo visitors as compared to such forecasts with feasibility rate as Gruber and Self-confidence indices. Thus, the findings of this study will provide researchers and event managers with appropriate forecasting method when predicting demand for mega-events.