Southern non-governmental organizations (NGOs) now act as important intermediaries in the transfer of agricultural science and technology for the development of Third World food production and markets. This paper presents an ethnographic exploration at the interface of Peruvian agricultural development NGOs and highland peasant communities, who are encouraged to leave subsistence farming and produce instead for wider markets. Following a methodology of symmetrical anthropology based in actor-network theory, I show how sociotechnical processes that underpin agricultural development rely on constructions of 'traditional' and 'modern' categories of practice in order to perpetuate efforts to change the peasant production methods. Yet as peasants appropriate and reinvent development's technologies and resources, NGOs are pressured to further control the 'discrepant' responses and behaviours of peasants. Focusing on a number of NGOs and indigenous, Quechua-speaking communities in the southern Andes, I argue that the incorporation of peasants into markets is made problematic by both entrenched racial tensions and the creative capacity of peasants to circumvent the disciplining and social planning strategies of NGOs.