This chapter describes how the regulatory frameworks for diagnostic technologies are changing, in part as a response to technological advances in personalised medicine. It provides an overview of how policy deliberation about the regulation of genomic diagnostics has evolved over the last two decades, and sets this policy debate in the context of broader concerns about the scientific rigour of diagnostic innovation. The chapter describes policy developments in the statutory regulatory regimes that govern diagnostic tests as medical devices; the construction of a new regulatory regime for pharmacogenomics; and the growing role of health technology assessment as a gatekeeping mechanism. It concerns about the scale and pace of innovation in genomics are indicative of an unresolved tension between personalised medicine and evidence-based medicine. The chapter argues that in comparison with the burgeoning literature devoted to pharmaceutical regulation, the regulation of diagnostic tests has been a relatively neglected subject for social scientists, historians and legal scholars interested in biomedicine.