The organisation of a bank of biological material as part of an epidemiologic study raises a number of problems. The first part of the paper discusses, in the context of the French regulation, the legal obligations, the administrative problems, the locations selected for the biological sampling, the strategy for sending out invitations to the participants, and the logistic of biological samples transport and storage. The second part presents the solutions brought to these problems in the prospective E3N-EPIC cohort study.