This presentation is concerned with the value of co-design in the interdisciplinary MedTech space. It will propose that, given appropriate conditions and materials, designing is an innate skill that can be released and practiced across disciplines to achieve a common goal. This will be illustrated through case studies showing the co-development of visual tools to assist in the physical rehabilitation of stroke survivors, and to train healthcare professionals in infection prevention and control. The audience will be invited to keep two thoughts in mind during the presentation, i.e. the need for the co-existence of a range of types of evidence and also the different types of engagement required in interdisciplinary research. The presentation will argue that co-designing in an interdisciplinary context is a distributed social accomplishment, that there is a need to understand (all) your potential end-users and to engage with them from the outset, that one's particular field of knowledge, abilities, prejudices and preferences may not be the only ones required to address a complex issue, and that one needs to ‘build to think’, to prototype and test iteratively, and to learn from mistakes early.