In Korea, the institutional reform for the national medical insurance system is in process. Eventually, three kinds of the national medical insurance system, i.e., medical insurance program for the industrial workers, the govemment employees and the private school teachers, and the self-employeds, would be merged into an unifed system. In this study, I analyzed the annual trends of the finance in the medical insurance system in Korea, in which I found the financial instability especially in the medical insurance program for the self-employeds. The regression analysis was carried out to forecast the accumulated reserve at the end of this year for the medical insurance program for the self-employeds. I also analyzed the economic effect of the merge of the medical insurance program for the self-employeds by using the case of Japan and Korea. I found that the medical insurance for the self-employeds is expected to have financial deficit at the end of the year 1998 after the merge. In onclusion, it seems to be quite difficult to solve the financial instability in the medical insurance program for the self-employeds after it would be merged. That means that there would be a lot of problems on the way to the merge.