Mekong Delta Development Research Institute (MDI) has cooperated with SEARICE to implement a project on Strengthening Farmer – Agricultural Research and Extension System Partnership in Vietnam for a period of 2011-2015; this project has covered 19 provinces in Vietnam and linked with the local institutions for supporting farmers. The project focused on three objectives: 1) Enhancing capacity of knowledge and practices for small farming households, 2) Mainstream farmer’s innovation systems, 3) contribute to policy actions towards participatory research and extension. The project trained for local extension workers and 2,685 farmers. 407 seed clubs were established to produce good seeds. These seed clubs contributed more than 30% of seed requirement of the Mekong Delta. Farmers have implemented many on-farm researches of doing crosses, seed selections, variety adaptation tests and farming practices to climate-smart agriculture. Farmer-breeders selected and released 130 stable lines for community use; some promising lines/varieties were grown with large area (about 50,000ha) in the Mekong Delta. On-farm researches showed that farmers who apply the improved practices reduce input costs and increase about 400 USD/ha/crop comparing to the traditional practices. Strengthening research capacity for farmers has been a good way to diversify agro-biodiversity for food security meet seed requirement in the Mekong Delta; and it has also encouraged farmer’s innovation for plant agro-biodiversity development and conservation. Then, the supportive policies for farmers working on participatory plant breeding and agro-biodiversity conservation should be concerned by the local government.