This paper juxtaposes the epistemological challenges raised by new agricultural technologies in India and China during the mid- to late twentieth century. In both places, the state actively sought to adopt the ‘improved’ seeds and chemical inputs of what USAID triumphantly called the ‘green revolution’; however, in neither country did this imply an unproblematic acceptance of the technocratic assumptions that undergirded the US programme. India and China's distinct ideological contexts produced divergent epistemological alternatives to the US vision, with particularly important differences in the perceived relationship between the sociopolitical and technoscientific realms and also in the understanding of what constituted a ‘modern’ farmer. In India, critics persistently challenged the technocratic state to consider social, political and economic aspects of agrarian modernization, but radical leaders in Mao-era China went considerably further in attacking the very notion that technological change could be divorced from social and political revolution. Leaders in both India and China sought to overcome ‘backwardness’ and ‘superstition’; however, the Indian state held up examples of farmers who exemplified capitalist ideals of modernity through their willingness to take risks in pursuit of profit, while Chinese leaders valorized peasant technicians who combined experience in labour, new technical knowledge and faith in socialist revolution.