On-farm conservation characterized by cultivation by smallholder farmers in agricultural and quilombola (formed by descendants of Afro-Brazilian slaves) communities is a tool for the maintenance of seeds and genetic diversity. Smallholder farmers who grow local varieties in diversity centers and communities contribute to supporting the capacity of agricultural and food systems to adapt to adverse conditions. Widely cultivated in the Northeast region of Brazil, lima bean (Phaseolus lunatus L), despite having relative economic and social importance, is little exploited in terms of conservation aspects. Based on a process of participatory interview, this article documents the knowledge of smallholder farmers associated with local varieties of this species, as well as the practices and strategies used for on-farm conservation in three producing areas of northeastern Brazil. The results revealed that farmers have a low level of education; the main factor for the loss of traditional knowledge is the disinterest of younger people in agriculture. The study highlights the importance of integrating scientific knowledge with traditional knowledge to develop sustainable agroecosystems, in which on-farm conservation is an alternative to diversifying agriculture, but which requires government and private support to stimulate and enhance agricultural activities and the interaction among smallholder farmers.