In Northwest Vietnam, mixed farms integrating crop and livestock are undergoing major changes driven by a multitude of factors: lack of labour force, reforestation law, limited land resources, and fluctuating markets. The changes in farming systems and practices raise questions about the future performance of farms and their role in the sustainability of the territory. This study aimed to assess the effects on farm performance of changing crop-livestock integration practices and farming systems at the farm level. A participatory workshop with local stakeholders was held to define prospective scenarios based on available knowledge of farming systems and their past evolution. The participants identified the drivers of change in practices and their impacts. A modelling tool has been used to simulate the effects of the scenarios on a diversity of mixed farms. The model used considers all biomass flows on the farm and between the farm and the other farms, the market and the environment (livestock and crop products, crop residues, forage and manure). Based on a set of indicators, the model assesses the effect of each scenario on the productivity, economic, environmental and social performances of farms. The five scenarios simulated were: the continuity of current practices (scenario A), the development of local feed self-sufficiency (scenario B), the implementation of environmental protection measures (scenario C), the development of intensive livestock farming (scenario D) and the development of quality livestock and crop products (scenario E). As expected, the simulation results show contrasting differences between farms. The results show which scenarios have the most positive effects on farm performances and highlight which farms are most affected by resource access limitations. These results could be used to support dialogue with local stakeholders on the expected development of crop and livestock systems and the sustainability of the agricultural sector.