The main objective of this study is to develop a model which describe and explain R&D productivity (Researchitivity measured by patents) in Korea four manufacturing industries-electric & electronic, machine, textile, industrial chemicals-during the last ten years. The model largely focuses on the variables related to R&D investment in order to investigate the efficiency of R&D. The results suggest that there is associated with a significant positive correlation between Researchitivity and industrial size. There are interaction effects between the Researchitivity and the sales volume. Researchitivity is positively correlated with the average wage of R&D employees. It also founded that Researchitivity is more closely associated with investment size than industrial nature.