This study constructs quantity and price indices of input and output of Korean agriculture for the period 1971-2007. By applying a dual approach the study decomposes the change in total factor productivity into scale effect, R&D effect and technical change effect. The contribution of the scale effect to the productivity change is the largest. However, it is shown that productivity growth rates higher than the usual level are explained mostly by the investment in R&D. In that sense R&D expenditure is the most important cause of productivity improvement in Korean agriculture. It is found that R&D investment in Korea saves labor, land intermediate inputs but uses capital input.