This paper examines, from the perspective of the structure-conduct-performance (S-C-P) paradigm, the structural factors that determine R&D concentration in industries. The results are as follows. First, an industry’s R&D concentration is directly related to its market concentration, R&D intensity, capital intensity, and technological opportunities. In contrast, the higher an industry’s performance, the more likely the diffusion of R&D investment is for firms belonging to that industry. Second, an industry’s R&D concentration has a positive effect on its market concentration but a negative effect on its performance, suggesting that governments should adopt R&D policies that would induce more firms to invest in R&D instead of focusing only on a few firms to enhance industry performance.