After the launch of Brazilian program of biodiesel use and production (PNPB) in 2004, the oil seed production became an economic alternative for family farmers since they might have the chance to improve their income and supply the biodiesel enterprises with raw material. Theoretically speaking this picture is easy to draw, but until recently little scientific research was carried out aiming at identifying the socioeconomic profile of farmers that are being included in the Brazilian biodiesel chain. Thus, this study aims to assess the linkages between family farmers’ living standard and the adoption of oil seed activity. Thus, an analysis of Jatropha curcas and Ricinus communis small-scale seed production was done in the Tocantins state, located in the north of Brazil. A fuzzy set theory was applied to construct deprivation indicators based on living standard criteria and a nonlinear logit model was formulated to analyze the inclusion of poor families in the biodiesel chain. The preliminary results point towards a positive relationship between degree of deprivation and adoption of oil seed activity in the case of Ricinus communis system production and a negative relationship in the case of Jatropha curcas system.