This paper deals with collaborative R&D projects, with a considerable number of organizational actors, which generate both new knowledge and innovations, market upstream. It is generally assumed that a large knowledge base is beneficial for knowledge generation due to more possibilities for recombination. But, under the pressure of project constraints, are bigger multi-actor projects indeed ‘better’, in terms of their innovation performance, measured by the number of their research and innovation outputs? The extant literature is contradictory on this topic. This paper sheds light on the relationship between the size of the projects and their research and innovation outputs, using an exploratory inductive multi-case study of multi-actor R&D projects funded by the latest European Union’s Research and Innovation Programmes. We provide evidence that over 95% of 185 research and innovation outputs in the studied projects were developed in small stable groups, or individually, independent of the project size: large knowledge base can be beneficial after the project but was not within the project. Nevertheless, the generation of meta-knowledge, a non-conventional project output not identified in the literature, may be a benefit of a larger project size in specific settings.