Tourism demand forecasting is important to reduce fixed costs and increase investment efficiency. Previous studies have shown that income elasticity and domestic economic variables were importance determinant factors of tourism demand. This study was to forecast domestic tourism demand of Jeju island employing the income elasticity and domestic economic variables as independent variables. Two different time series data set, which was collected by Jeju Tourism Board and Statistics Korea from 1962 to 2010, were used for the forecasting. Results showed that domestic tourism demand of Jeju island was more sensitive than economic growth rate. Results also indicated that the honeymoon market might be substituted for the outbound market unless it was influenced by the external variables such as exchange rate and oil price. Moreover, overseas trip rapidly replaced the domestic trip to Jeju from 1998. Several implications were presented on the basis of the research findings.