An endogenous growth model, in which technical change is attained through public and private R&D activities, is utilized to explore the role of technical change in TFP growth, to determine the impact of public and private agricultural R&D investments on the flow of agricultural patents, and to analyze the determinants of private agricultural R&D spending. The implications of the theoretical model are tested empirically for the U.S. agricultural sector. The empirical results are consistent with the theory. The main finding is that there is a positive relationship between TFP growth in the agricultural sector and agricultural patents. Current and past public and private R&D investments in agricultural sector have a significant and positive effect on agricultural patents. It is found that public R&D investment does not crowd out private R&D investment.