Although a few jurisdictions around the world have legislated in response to the phenomenon of biobanking, the far more common response has been policy led with funders and other stakeholders initiating multi-level policy initiatives to guide biobanking practice. An example of this is UK Biobank which has developed and operates according to an Ethics and Governance Framework. Such an instrument has no basis in law and yet it has played a crucial role in the set up and ongoing management of the resource. It will continue to do so, as related policies emerge, such as access and intellectual property policies. Numerous biobanking initiatives have similar high-level policy documents that guide decisions and practice. These are often framed as a commitment to participants, researchers and society more broadly and invoke notions such as the public good and the public interest. As such, they serve as a benchmark against which to measure a biobank's performance. Moreover, policies become an important means by which biobankers are held accountable. This article critically analyses this policy-driven phenomenon asking how effectively policy--often as an alternative to law--serves to police and to promote biobanking. It argues that a policy of reflexive governance--defined and developed herein--can best meet the challenges faced by many biobanks and without the need for recourse to law.