The moderating effect of employee turnover rate on the relationship between investment on HRD(Human Resource Development) and organizational performance was explored in this study. The population for this study was the corporations of manufacturing industry in the Republic of Korea. The HCCP(Human Capital Corporate Panel, 2005) data was used for this study. After checking the data to confirm that all data were appropriate for this study, finally, the data from 281 corporations were used for the data analysis. The investment on HRD variable was measured by the annual training and development expenditure, the organizational performance variable was measured by the net profit per employee, and the employee turnover rate variable was measured by the total number of regular employees turnover divided by the total number of regular employees. Organizational size, which was measured by the total number of employees, was introduced as a control variable. All data were measured in 2004. Descriptive statistics, hierarchical multiple regression, and two-way ANOVA were introduced to identify research questions. It is identified that the investment on HRD has a positive effect on organizational performance, the turnover rate has a positive effect on organizational performance, and the turnover rate moderates the effect of HRD investment on organizational performance. The implications of these findings for future researches and practices are discussed.