Integrating crop and livestock activities at the farm level is commonly proposed by research programs in sub-Saharan Africa as a way to sustainably improve farm productivity. This integration process requires farmers to change their knowledge, perceptions and practices to achieve sustainable intensification. This article presents a participatory support approach based on an analysis of farmers' current practices and knowledge and a simulation tool designed to facilitate interaction with farmers. It was tested in western Burkina Faso with 18 farmers representing three farm types defined by their balance between crop and livestock activities. Although a low level of crop-livestock integration was observed, every farmer recognized a positive link between the production of organic fertilizer and plant production. However, only one third of the farmers linked plant production with fodder and animal production. By building and simulating various integration scenarios, every farmer developed a deeper understanding of systemic interactions between crop and livestock activities on his farm. Project scenarios including the storage of biomass and animal stabling were evaluated. Although these innovations improved the farms' capacity to fertilize cereals and to feed herds, the structural changes involved were perceived to be difficult to implement, either for economic reasons at the farm level, or because they involved changes in biomass management at the community level. However, the support process led to tactical changes the following year, with 80% of the farmers increasing their storage of crop residues and organic manure. The approach was useful for farmers to evaluate and eventually implement possible innovations, and for researchers to better understand the constraints and limits farmers face when seeking to better integrate crop and livestock activities.