In recent decades, we have witnessed in most countries a slowdown in the rate of growth in spending on agricultural Research and Development (R&D) — especially R&D oriented to enhancing farm productivity. This trend is most notable in the world’s richest countries that have in the past been the primary drivers of global agricultural science and innovation. It has happened in spite of compelling evidence on the very large returns to public investments in agricultural R&D. Along with the slowdown in research investments we have witnessed a slowdown in agricultural productivity growth in most countries — China and Brazil are notable exceptions. These trends have potentially significant implications for global food security unless policy changes are implemented soon to rapidly reinvigorate investments in agricultural science and innovation, especially in view of the very long time lags between making investments in R&D and reaping returns in farmers’ fields.