This study compared and examined recent trends of university entrance examination reforms in Japan and South Korea, focusing on discussions on the “diversification” of entrance examinations. First, the author raised the decline of the 18-year-old population as a common internal factor concerning university entrance examinations in both the countries, and identified that this factor could contribute to the rise in the university entrance rate as well as the diversification of the admission process. At the same time, the author identified that the adopted methods of admission could be differentiated along the demarcation between national or public universities in Japan, while between the metropolitan area and the non-metropolitan area universities in South Korea. Next, as to the “diversification” of university entrance exams, the author examined the transformation of various admission methods in the two countries: “comprehensive selection” and “school recommendation type selection” in Japan, and “student book-centered selection” in South Korea. In Japan, discussions centered on the definition of the academic ability and the evaluation method concerning the two selection methods mentioned above, and the specific evaluation method was presented. On the other hand, in South Korea, strong government-led measures have been taken, focusing on the conceptions of “fairness” and “social gap” originated from the diversification of entrance examinations. In the process of its realization, governmental financial support and sanctions were applied, resulting in the weakening of university “autonomy.” The author considers that the issue of “fairness” has been a noteworthy aspect newly added to the recent trend in Japan, and as to the problem, South Korea s long-standing experiences and studies could be helpful. And South Korea may refer to Japan s discussions on the issues of “academic ability” and evaluation methods, which have been often forgotten in South Korea’s discussions for ensuring “fairness” and diminishing “social gap.”