Throughout Africa, per capita food production has been declining since the early 1960s. Cameroon has sought to counter this trend by increasing agricultural productivity through research and extension. In order to establish future investment priorities, policy makers need to know if past agricultural research investments have earned sufficient returns to justify continued funding. Further, national experiences need to be compared to see if returns varied across programs, and in cases where they did, explanations need to be sought to discover why these variations exist. To address these issues, data were collected in Cameroon and analyzed in order to estimate the benefits and costs of investments in sorghum and cowpea research and extension in northern Cameroon. Specific data that were needed to construct benefit and cost streams included the following: yields of traditional and introduced technologies, area harvested, adoption rates of technological innovations, prices of both inputs and outputs, climatic factors influencing both the research agenda and the returns to this research, and the costs of research and extension efforts. Focusing on the period 1979-87, the analysis addressed three questions: What were the returns to past investments? What factors explained the estimated returns and any variability in returns between the sorghum and cowpea programs? And how did institutions influence these returns and the distribution of their benefits?