Key activities in biomedicine and related research rely on collections of biological samples and related files. Access to such resources in industry and in academic contexts has become strategic and represents a central issue in the general framework of rising patenting practices and in debates about the knowledge economy. It raises important issues concerning the organisation of scientific and medical work, the outline of data-sharing guidelines, and science policy's contribution to the elaboration of an adapted framework. This paper presents an (...) ethnographic study of three French human biobanks. Building on field work (participant observation and in-depth interviews), the study focuses on data access in the concrete practices in biobanks. The paper develops a perspective based on an analysis of different exchange regimes. We argue that access practices are submitted to the different regimes that can coexist and be articulated within the daily activities of each biobank. We also discuss how this perspective can further our understanding of biomedical research, and how it might inform data access policy. (shrink)