In Brazil, various types ofpeasant farmer arrangements, dedicated primarily to supporting individual or family production, have been taking on functions of public interest. The peasants ensure these functions through relationships of cooperation and reciprocity (mutual aid and sharing of common resources). These collective and institutionalized "arrangements" are dedicated to the management of common natural resources (water, land, pasture, forest, native or local seeds) or to the production oflocal public goods (knowledge, innovation, or access to markets). This paper analyses the main characteristic of some of these experiences and examines how they could contribute to the policy making ofrural development public tools more appropriate and efficient.