The MRC Prion Unit was established in 1998 and is located at the UCL Institute of Neurology where it is closely integrated with the University Department of Neurodegenerative Disease. The Unit was formed to provide a national centre of excellence with all necessary facilities to pursue a major long-term research strategy in prion and related diseases. Prions, unlike other infectious agents or germs, appear to lack their own genes and consist of aggregated misshapen forms of one of the body’s own proteins, the prion protein or PrP. Despite lacking genes, prions can exist as distinct strains with quite different properties. These unique features have wide implications in biology and evolution, and prions and prion diseases are of intense international research interest. However, in addition to the importance of this basic science, the Unit’s mission is also to tackle key public health issues posed by bovine spongiform encephalopathy (BSE) and variant Creutzfeldt-Jakob disease (vCJD). It is becoming increasingly clear that other much commoner degenerative brain diseases, such as Alzheimer’s and Parkinson’s disease, also involve accumulation of rogue or abnormal forms of one or more of the body’s proteins resulting in damage to brain cells. Prion diseases, in addition to their intrinsic interest and importance, can be considered a paradigm for these other “protein misfolding” diseases. Our research programmes are highly multidisciplinary and focus both on areas of public health concern and a long-term approach to the understanding of prion disease. They include studies of molecular structure, genetics, biochemistry, immunology, cell and animal models, and clinical research - including treatment trials. Two major programmes to develop novel therapies are underway. Our research philosophy is to seamlessly combine basic (laboratory) and clinical (patient-based) research. Many of the key contributions towards understanding the biology of these diseases have come from clinical and neuropathological observations. Efficient translation of these basic studies to enable better early diagnosis, prevention, and effective treatments, is crucial. A UK-wide tertiary referral service for patients suspected to have, or at risk of developing, any form of prion disease - the National Prion Clinic (NPC) - is based at the adjacent National Hospital for Neurology and Neurosurgery and is closely integrated with the Unit allowing all patients who wish to participate in research to do so. The Unit provides a key training resource and centre of specialist expertise in this unique area of biology and medicine and supports the development of neurodegenerative disease research more widely. The Unit has many local, national, European and other international links and collaborations in prion and other neurodegenerative disease research, and provides an authoritative independent source of advice and opinion in what continues to be an area of major scientific, public health, animal health, political and economic importance.