DNA vaccination, or genetic immunisation, has progressed from initial observations 20 years ago through to commercial reality today. Along the way, there have been some stunning successes, including the first experimental vaccination of American condors, to protect them from devastation by the West Nile virus, through to the commercialization of the West Nile viral vaccine for use in horses. Along the way, a large number of research publications have detailed the uses of DNA vaccination as an attempted prophylactic and therapeutic strategy. This chapter will review the short history of DNA vaccination, the underlying immunology and technology, and some of the current and future applications of this revolutionary vaccination technique