The general objective of CAT (Tocantins Agro-ecology Centre) working in a Brazilian Amazonia frontier region, is to improve the living conditions of low income farmers. It is based upon a liaison between researchers and farmers' organisations. After five years of operation, we have noted that these organisations' participation in the direction of the programme, and especially the research itself, develop in the way that was hoped. Firstly, the small farmers' organisations are going through a transition period which is reflected both in their practices and in their self-identity. They are having problems drawing up proposals which would attract more small farmers. Secondly, the research team needs to develop more sensitive scientific tools to build a dialogue with farmers. We analysed the obstacles to this dialogue. Starting from the principle that the process of development of knowledge can be stimulated by discussion among small farmers, and between small farmers and researchers, an attempt was made to set up a process which encouraged dialogue between the world of research and the world of development.