This paper uses a Rural Investment and Policy Analysis (RIAPA) model for the mainland Tanzania economy to identify the agricultural activities and value-chains whose expansion will be most effective at fostering economic development along four dimensions: generating economic growth in the agricultural-food sector of Tanzania; reducing national and rural poverty; generating employment; and improving nutrition by diversifying dietsThe results of scenarios run through the model suggests that there is no single value-chain that can achieve all of the policy objectives.