Reductions in poverty and improvements in food security are important issues for farmers and agricultural regions in Cambodia. In this paper we relate our approach and experience working in upland areas of Battambang Province to improve agricultural, environmental and social outcomes for farm families and villagers. Small farm sizes and observed low levels of agricultural productivity exacerbate poverty and food insecurity. We have approached this challenge by first investigating and demonstrating new agricultural methods (or technologies) in a farming systems context, through developing a network of farm trials and demonstrations. To this is added activity in contextual economic and social assessment of new versus old farming methods and management, with the objective of farmer adoption of improved methods and associated increases in farm family incomes. We have formed Crop Profit Groups of local farmers to assess the economic costs and benefits of changed management in the main cash crops of maize and soybean. We have also investigated marketing and value-chain issues since these affect upland farmers in important ways. Our approach has been to bring expertise to each situation and adopt a co-learning approach with local farmers, government officials and NGOs. Education and capacity-building of Cambodian collaborators has been an important part of the work. While our work is not yet finished we have found a genuine willingness by the Cambodian farmers to consider new 'ways of doing things' and be involved in assessing their own incentives to change. A variety of approaches are used in training and capacity building of the local researchers and officials. There seem to be substantial economic incentives to change some farming practices, but issues of farm input supply availability, markets and prices received for farm produce, transport costs and infrastructure appear to constrain improved farm and regional outcomes.