The international transfer of human biomaterial and data has become a prerequisite for collaborative biomedical research to be successful. However, although a national legal framework for 'biobanking' has already been formulated in many countries, little is known about how an international exchange of data and samples might affect the legal position of national biobanks and their donors. The German Telematics Platform and the Competence Network 'Congenital Heart Defects' jointly instigated a project (BMB-EUCoop) to (i) identify and assess the legal risks ensuing for biobanks and their donors in the context of Europewide research collaborations, (ii) devise practical recommendations to minimize or avoid these risks, and (iii) provide generic informational text, contracts and agreements to facilitate their practical implementation. Four different countries were included in the study; namely, the UK, Netherlands, Austria and Switzerland. The results of the study indicate that the degree of similarity between legal systems in different countries varies according to the respective field of jurisdiction. Although personality and property rights have long been enshrined in virtually identical pieces of law, the applicable medical professional regulations were found to be somewhat heterogeneous. Furthermore, clear-cut differences were often found to be lacking between regulations that reflect either 'soft law' or the nationally binding 'hard law' that has emerged from it. In view of the potential ambiguities, the experts uniformly concluded that the rights and interests of national (in this case, German) biobanks and their donors would be best protected by explicitly addressing any uncertainties in formal contractual agreements.