The Farmer Field School (FFS) is a form of adult education using experiential learning methods, aimed at building farmers' decision-making capacity and expertise. The National Research Institute in West Africa conducted FFS in cowpea cultivation and we use this experience to analyse the implementation of the FFS approach. How does it work in practice? The curriculum deployed is compared to the "principles" for FFS curricula. We assessed the impact of the FFS on the implementation process of Integrated Pest Management (IPM) practices in farmers' crop management. The appreciation of different stakeholders is also recorded. The analysis shows that the FFS was used as a tool to transfer messages, rather than to foster experiential learning among farmers. The article seeks to analyse the reasons for this shift in objectives and concludes that the way in which the FFS approach was applied in the case of the cowpea project did not allow optimal benefits to be derived from IPM practices. (Contains 1 table.)