This paper describes a comparison on farmers’ participation in farmers’ organisations and attempts to explain why they prefer to carry out production and marketing activities by themselves. It also examines the implications of the findings for rural extension and related services. A total of 122 interviews were conducted with different categories of farmers and with the extension workers. The comparative analysis of two case studies (Cruz Alta and Pantano) showed that socio-economic characteristics were not very significant in determining the level of farmers’ participation in farmers’ organizations in Minas Gerais. The ability of managers emerged as one of the most important factors in the success or failure of farmers’ organizations. The presence of private competitors can also greatly determine the direction and the destiny of the whole process. Another relevant conclusion is that farmers are more predisposed to participate when the organisations offer additional benefits to them, such as tractor services and sale of inputs. The research findings show that the role of rural extension should be more related to providing more advice on participatory activities and management techniques to farmers’ organisations. The major implication of the findings for rural extension, and other institutions involved in the development of rural communities and farmers’ organisations, relates to the importance of putting more emphasis on providing knowledge to local people in the technical aspects of managing collective businesses.