This study empirically analyzed the impact of variables related to CEO turnover on R&D investment, such as CEO turnover rate, timing of turnover, and type of turnover. In addition, the study examined the impact of Chaebol governance on the relationship between CEO turnover and R&D investment. It was aimed at explaining the phenomenon of continuous R&D investment being made even during the relatively short term tenure of CEOs of Korean firms through the moderating effect of Chaebol governance. The empirical analysis results are as follows. First, the more frequent CEO changes were made, the less R&D investment was made. Second, an analysis of R&D investment before and after CEO turnover showed that R&D investment decreased significantly in the year of turnover and one year after the turnover of CEO. Third, the effect on R&D investment was different depending on the type of CEO turnover. Fourth, as a result of considering Chaebol governance structure at the same time, it was confirmed that Chaebol governance controled the inducement for reducing R&D investment due to the replacement of CEO of individual company. These results suggest that studies should simultaneously consider the effects of Chaebol governance, along with the characteristics of individual firms.