ABSTRACT.- Achieving sustainable food and nutritional security requires a transformation of the existing agrifood system. In livestock farming based on natural grassland in Uruguay, an ecological intensification strategy could play a radical role in the transition towards more sustainable systems. This study analyzes the continuity of interconnected projects that used co-innovation approaches to promote and evaluate ecological intensification strategies over a period of 15 years (2004-2019). The purpose of the article is to provide evidence on the development of a socio-technical niche in sustainable livestock farming and to identify anchoring points for further regime transformation. Our contention is that interactive research in the context of application based on a sequence of co-innovation projects has the potential to trigger a sustainability transition through ecological intensification of livestock farming based on natural grassland. The research followed a single-case study design with multiple units of analysis, based on the study of documents produced by the different projects and semi-structured interviews. In addition, network analysis was used to examine the linkage of persons and projects. Results show that a socio-technical niche in sustainable livestock farming base on natural grassland was developed in Uruguay, promoted by research institutions and progressively involving other social actors throughout the process. The continuity of projects over 15 years, was fundamental to achieve the three essential processes for a niche conformation: i) an alignment of expectations and the development of a common vision, linked to the sustainable development of family-farming; ii) the creation and expansion of a network of stakeholders, comprising researchers, farmers, extensionists, and other relevant actors; iii) the development of learning processes through interaction, accumulating knowledge around two main axes: a new way of promoting innovation through research in application contexts associated with co-innovation, and a new way of sustainable livestock farming associated with ecological intensification. This study reveals the importance of sequencing co-innovation projects and continuity in the negotiation of visions of change, the creation of a community committed with the direction of change, and the promotion of interdisciplinarity and interactive learning, that foster changes at a socio-technical level. Anchoring challenges, and therefore advancement of the transition process, face the need for significantly expanding trained research and extension personnel to implement co-innovation and ecological intensification practices in livestock systems, and the organization of an extension program to sustain long term transformation of livestock farming in Uruguay. © 2022 Elsevier Ltd. All rights reserved.