Achieving efficient, sustainable and smallholder-inclusive staple food systems often require strong, credible, and economically effective producer organisations. In much of Africa, and particularly in West and Central region, this objective remains a great challenge for the majority of small farmers, as existing producer organisations often suffer from weak structures, inadequate governance, and limited internal capacity to provide economic services for their members, engage credibly with economic and institutional partners, or influence policies for effective smallholder market integration. This report describes a new methodology called GAIN (Governance - Autonomy-Integration-Needs based) developed by FAO to provide an effective diagnostic tool for designing and inducing an endogenous change within farmers organisations, and placing them on a path of economic autonomy, self-reliance, and enhanced market insertion.GAIN follows a participatory and iterative approach, combining an internal diagnosis of the organisation with an analysis of the immediate economic and institutional environment in order to identify and leverage new options for economic partnerships, capacity development, and market and business opportunities. One of the outcomes of GAIN is a roadmap for the organisation towards a gradual economic empowerment, enhanced ability to provide economic services for its members, and play a more active role in the local rural economy. The report describes the GAIN methodology and presents a detailed account of its application in three case studies involving actual producer organisations from Burkina Faso, Cameroon and Mali.