Integrating two or more animal species with crop production or agroforestry on a farm potentially provides many benefits including more efficient pasture use and parasite management. However, organic mixed livestock farms (OMLF) tend to specialize or display limited integration between farm components. This limited integration may reduce the practical benefits of OMLF. Therefore, this project aims to (i) characterize OMLF in Europe, especially their level of integration between farm components, (ii) assess their sustainability and robustness to adverse events, (iii) compare their performances with those of specialized farms, (iv) integrate the knowledge developed on OMLF into models that can simulate their performances against climatic and economic variability, (v) conduct farm-level experiments to generate knowledge about OMLF (to feed into the models) and (vi) co-design more sustainable and robust OMLF with farmers. We will survey OMLF to collect technical and socio-economic data. Then we will enlarge existing concepts and methods to assess the level of integration between farm components and apply these methods to surveyed OMLF. We will also develop an indicator system for integrated assessment of OMLF and apply it to connect the sustainability and robustness of surveyed OMLF with their level of integration among farm components. In parallel, we will conduct farm-level experimentation of organic specialized and mixed livestock situations for the comparison of specific aspects of animal husbandry (e.g. pasture use, animal health). We will extend farm simulation models to OMLF and analyse the benefits and drawbacks of livestock diversity. Using these models, we will develop and implement participatory methods to co-design with farmers sustainable and robust OMLF. To inform practice and policy-making, we will communicate our results to shed light on the potentialities of OMLF and the way to manage it sustainably or the way to reach it starting from a specialized farm.