This paper assesses the motivation behind the decisions of smallholder farmers to volunteer as farmer trainers despite the fact that they are not paid for their services. The farmer trainers are volunteers selected by the community on the basis of being good communicators and interest in sharing knowledge on fodder innovations. They are trained in livestock feeds and feeding methods by extension officers. They in turn share the knowledge with other farmers in a participatory manner through demonstrations and interactive learning. A study was carried out to understand the motivations of smallholder farmers to volunteer their time to train and share their knowledge with other farmers without pay. Collection of data was through a combination of focus group discussions and individual interviews with 99 and 190 volunteer farmer trainers (VFTs) in Kenya and Uganda respectively. Findings of the study showed that VFTs were motivated by a combination of intrinsic and extrinsic factors. Knowledge and altruism were found to be the most important motivating factors for becoming trainers and even three years after becoming trainers in the two countries. Other factors are social and project benefits. Three years after becoming trainers, income earned from selling inputs and specialized services was a main motivating factor to VFTs in Kenya than Uganda. Reasons  are explored in the paper. Demand for training also emerged as a motivating factor after VFTs started sharing their knowledge. The findings point to the fact that the general reasons that motivate volunteers irrespective of context are driven by personal and community interests. However, certain motivations are context specific.