This paper presents the experiences and lessons obtained in conducting on-farm participatory research in North Omo, Ethiopia, by an foreign NGO. It highlights how PRA techniques are used in the on-farm trials programme. The objective of the project Farmers' Research Project, is to raise incomes of resource-poor households by improving agricultural technology. Farmers' participatory research is the key approach adopted. To achieve this, the agricultural and extension staff on the project were trained in participatory approaches to enable them incorporate farmers participatory research (FRR) into their own work programmes. The paper discusses how farmers are involved in the decision making process about the research which in itself, is an innovation of farming systems research. The paper mentions that one of the ways farmer participation is achieved is through conducting on-farm trials by going through the stages of diagnosis, planning, implementation and evaluation, using PRA. Each stage is discussed in the paper. In conclusion, the paper mentions the mutual respect of both staff and farmers as experts, close contacts and cross visits as approaches that played an important role in raising the level of understanding.