This paper explores enactments of participation in two Swiss bi- obanking configurations, a cohort biobank and a general biobank. It sheds light on the role of Personalized Health endeavours, in which biobanks play a crucial role. In order to contribute to the understanding of the role of par- ticipation in biomedical research dynamics, the analysis focuses on the pro- cesses of co-production of identity and biobanks (Tupasela et al. 2015). It documents the overlaps between the population – providers of biological samples – and the public, the collective who is expected to give its opinion on issues raised by the reconfiguration of the research/healthcare interface. It shows that modalities of participation impact the potential scientific value derived from the biobank’s population, but also that the reconfiguration of the research/healthcare interface at the core of biobanking contributes to the current blooming of discourses and practices of participation. It argues that the forms of collective identity shaped through participation as popula- tion and/or public, exceed formal strategies of participatory governance and may play an even more important role in the shaping of biobanking configu- rations.