This study intends to examine the size and characteristics of immigrants living in Korea and analyze the difference in their fiscal contribution according to their characteristics. Based on this analysis using a dynamic equilibrium model, it is aimed to critically examine the direction of Korea’s immigration policy as a response to fiscal problems caused by population aging. First of all, this study surveys the trends in size and characteristics of immigrants staying in Korea. According to various statistics, it is found that the number of immigrants is increasing relatively rapidly and this increasing trend is explained mainly by the number of immigrants with long-term visas admitting for one year or more. Immigrants exhibit higher labor force participation rate and employment rate than domestic working-age population, but tend to stay in Korea for shorter periods than immigrants of other OECD countries. Female immigrants with marriage visas have higher fertility rates than domestic women. Next, based on these empirical facts, a dynamic equilibrium model is designed to estimate the net fiscal contribution of immigrants in Korea. Using this model, it is computed how net present value(NPV) of future fiscal contribution differs by visa types, age, and other characteristics of immigrants. According to the model analysis, it is found that NPV of young and productive immigrants can be positive. However, the sum of the NPV of all immigrants in Korea is negative, implying that an immigration policy reform which only increases the inflow size while maintaining the current foreign population structure, can worsen Korea’s fiscal problems. This analysis suggests that immigration policy reform might exacerbate Korea’s fiscal soundness if it simply targets to maintain the numerical balance of demographic structure. A selective immigration policy, considering qualitative factors such as immigrants’ productivity, age, and participation in economic activities, might be more desirable in order to minimize potential fiscal burdens.