There are few studies that directly address the upskilling issues in developing countries. Since theoretical analyses of these issues usually yield different results, upskilling in developing counties, and the factors of upskilling, if any, are rather empirical questions. This study shows that upskilling that occurs in developed countries in terms of the ratio of the number of white-collar workers to that of blue-collar workers also occurred in the Republic of Korea, one of developing countries. Increasing demand for highly-skilled workers reflected in their employment and wage shares can be largely explained by "within industry" shifts, not by "between industry" shifts, especially in the manufacturing industry. To further investigate the causes of these shifts, changes in white-collar shares are regressed on the capital-output and R&D-sales ratio. Estimated coefficients are all positive, suggesting capital-skill complementarities and skill-biased technological change.