The Participatory Market Chain Approach (PMCA) stimulates innovation among actors along agricultural value chains. It builds trust between farmers, intermediaries, processors, retailers, consumers, and research organizations. Over multiple phases, PMCA uses participatory analysis and group work to identify market opportunities and develop new products, technologies, and institutions. It has helped transform native potatoes from a staple crop into value-added products in Andean markets. Lessons show PMCA is most effective when combined with other programs and evolves over time, sparking second and third generation innovations. It has also been adapted successfully in other regions through approaches like Farmer Business Schools in Indonesia.