SALSA will assess the role of small farms and small food businesses in delivering a sustainable and secure supply of affordable, nutritious and culturally adequate food. SALSA will identify the mechanisms which, at different scales, can strengthen the role of small farms in food systems and thereby support sustainable food and nutrition security (FNS). By considering a gradient of 30 reference regions in Europe and in Africa, we will obtain a differentiated understanding of the role of small farms and small food businesses in very differently structured food systems and situations. SALSA will elaborate and implement a transdisciplinary, multi-scale approach that builds on and connects relevant theoretical and analytical frameworks within a food systems approach, and that uses qualitative, consultative and quantitative methods. We will also test a new combination of data-based methods and tools (including satellite technologies) for rigorously assessing in quantitative terms the interrelationships between small farms, other small food businesses and FNS, paying particular attention to limiting and enabling factors. SALSA will use participatory methods, at regional level, and establish a more global Community of Practice and multi-stakeholder learning platform, based on FAO’s TECA online communication and learning platform.The SALSA consortium, and the joint learning and close cooperation, have both been designed with the EU - Africa dialogue in mind. Responding to the call we will unravel the complex interrelationships between small farms, small food businesses and FNS, and unfold the role played by small farms in (a) the balance between the different dimensions of sustainability, (b) maintaining more diverse production systems, (c) supporting the urban/rural balance in terms of labour and (d) in facilitating territorial development in countries facing a strong rural population growth.