This document summarizes a case study on the role of radio-based extension services in Malawi. It outlines the history of radio use in agricultural extension in Malawi since 1958. Key lessons learned from Farm Radio Trust projects between 2007-2013 include: (1) radio can increase farmers' knowledge and improve agricultural practices, (2) radio is most effective when programs are developed by and for farmers, and (3) radio can trigger demand for improved face-to-face extension and other support services. The case study highlights the importance of participatory radio campaigns in driving demand-led extension.