AbstractThis chapter has three contributions. The first one examines farming systems (FSR) extension in the USA, drawing attention to two cycles of FSR in extension in the country, first in the 1920s and 1930s when extension agents first sought to address the farm as a whole and latterly, since the 1980s with participatory approaches growing stronger and farmers becoming more concerned about the sustainability of their systems. The second contribution tracks the role of FSR in the evolution of the extension services in Chile. Farming systems development for policy formulation is described in the last contribution.