Ethical guidelines commonly state that research subjects should have a right to withdraw consent to participate. According to the guidelines we have studied, this right applies also to research on biological samples. However, research conducted on human subjects themselves differs in important respects from research on biological samples. It is therefore not obvious that the same rights should be granted research participants in the two cases. This paper investigates arguments for and against granting a right to withdraw consent to research on biobank samples. We conclude that (1) there are no explicit arguments for such a right in the guidelines we have studied, (2) the arguments against such a right are inconclusive, (3) considerations of autonomy, privacy, personal integrity, and trust in medical research provide sufficient reasons for granting a right to withdraw consent to research on biobank samples, (4) in certain cases, research participants should be allowed to waive this right.