This chapter explores some of the linguistic aspects of informed consent to genetic biobanking, defined as the collection and storage of DNA samples and derived information for present and future research purposes. Drawing on the linguistic literature, the chapter examines informed consent from the perspective of speech act theory. Qualitative analysis of interviews with people recruited to join either of two biobanks focuses on the signing of the informed consent document as a performative speech act with practical and legal consequences. It is, however, an “empty” performative, in that subjects express little—and often incorrect—understanding of the implications of their consent. The analysis also reveals the giving or withholding of informed consent to be a complex and often lengthy discursive process. The ceremony at which the informed consent document is signed is but one step in this process, and, from the subjects’ perspective, rarely the most significant one.