The twentieth century saw substantive shifts in the structure, funding and conduct of public agricultural research and development (R&D) and related regulatory and extension activities in South Africa. Following a long period of steady (and at times quite rapid) growth beginning in the early twentieth century, real spending on public agricultural R&D has essentially flat lined since the 1970s. There has also been an erratic pattern of funding per scientist and a loss of scientific personnel in recent decades. Notably, South Africa has lost ground relative to its competitors in international commodity markets, such as the United States (US) and Australia in terms of the intensity of investment in agricultural R&D. In the absence of changes to these trends, these developments may well have enduring, and detrimental, consequences for the productivity performance and competitiveness of South African agriculture. They deserve serious policy attention as the twenty-first century unfolds, with a firm eye to the long-run given the lengthy lags (often many decades) that typify the relationship between public agricultural R&D spending and productivity growth.