To foster agrirultural development. a nmnber of strategies are available. A well-known, long-run strategy is productivity-increasing research. Another familiar, shon-run strategy is input and output price policy. This paper argues that effectiveness of price and research policies can only be obtained if they are defined interactively, with one complementing the other. This is illustrated by showing how cassava, a traditional crop in Latin America, has evolved with respea. to research and price policy over the last few decades. Three main dimensions are distinguished. The first is appropriate timing of research and price policies in relation to changing structural features of the economy. The second is price policy to support diffusion of research-based technology. The third is definition of research policy in relation to the socioeconomic envirorunent in order to maximize the impact of price policies. The historical development of Latin American agrirulture and cassava's position within it over the last 10 years is used to illustrate these points. A major problem in obtaining more consistent and development-focused research and price policy is that the locus of decision making for these two policies is often in completely different institutions.