This study was conducted in Trans Nzoia District and it pursued the concept of farmer participation in agroforestry extension with particular reference to small-scale farmers. The study identified extension methods and the extent to which extension agencies have involved the farmers in extension services. Emphasis was laid on factors inhibit framers' participation both at the agency and farmer levels. The study further examined the existing local potential among farmers and within their environment that could be harnessed to promote sustainable agroforestry practices. In carrying out the study, a questionnaire, an interview schedule and a guide, and an observation record sheet were used to collect data. Data collected were collated, coded and analysed using SPSS 6.1 version. Data were analysed descriptively using multi-response cross-tabulations and contingency tables that generated frequencies and percentages. Additional descriptive analytical tools, such as SWOT analysis and content analysis were used to treat descriptive data generated by focus group interviews with small-scale farmers and interviews with the extension fraternity. Statistical significance testing was also employed using the Chi-square at 0.05 alpha levels to test differences, relationships and associations between variables. The study identified six principal methods in agroforestry extension. There was however, a variation between the methods used across institutions although a shift towards group approach by majority of the institutions was revealed. Additionally, farmers were involved in the initial stages of planning, decision-making and implementation. In the other levels of participation, i.e. monitoring and evaluation, farmers' inputs were conspicuously absent. The study further revealed that farmers who had participated in extension programmes were better adopters of agroforestry than those who had not. The study established constraints at the agency and farmer levels inhibiting the implementation of participatory extension programmes. Constraints at the agency level included staffing inadequacies with regard to number, training and motivation, paucity of support resources in transport and back-up literature, and poor inter-agency co-ordination. These problems implied poor preparation in implementing participatory methods in extension. Farmer-centred problems included poor funding of groups, poor attendance of meetings, passiveness of group members, and conflicts among farmers. Finally, the study revealed a wealth of indigenous knowledge in seedling production and tree management. Farmers also exhibited a deep grasp of knowledge on tree uses reflected in their preference for particular tree species. The study further found out that the existing local potential among farmers has been less utilized in the planning and implementation of extension programmes. From the study's findings, many options exist for future extension contact, among them the local groups hitherto overlooked in extension delivery. Based on the research findings therefore, the study recommends the provision of an enabling environment by extension agencies to facilitate the effective implementation of farmer involvement in extension programmes. This demands the review of policies and restructuring of the institutional framework within which agroforestry extension takes place to overcome the major constraints faced by the institutions in this respect. Hence support and commitment is needed in the areas of physical and human resource development to overcome constraints of staffing and support resources. This should also include inter-agency coordination, the building of an effective monitoring and evaluation mechanism, and exploring other options to enhance the role of farmers in extension programmes to galvanise the existing extension efforts. The research concludes by proffering recommendations for areas of further research that are necessary if the concept of farmer participation is to be fully realised.