Veterinary vaccines need to have desired characteristics, such as being effective, inexpensive, easy to administer, suitable for mass vaccination, and stable under field conditions. Genetic vaccines, particularly DNA vaccines, have the potential to overcome conventional vaccination platforms, thanks to their safety, ease of production, and stability, especially for veterinary applications. Many aspects, such as antigen engineering, vector design, and delivery methods, are still being investigated because of their great influence on immunogenicity and efficacy of DNA vaccines. In this regard, among the different delivery solutions that have been tested in small and large animal species, gene-electrotransfer (GET) represents the most efficacious way to improve DNA vaccine immunogenicity. Several important issues need to be addressed when developing DNA vaccines for animals, including whether or not the vaccine is efficacious and cost-effective compared with currently available options. Moreover, it is crucial how to apply this developing technology in a wide range of different situations, from the domestic pet to livestock with several thousand animals to wildlife programs for disease control. This chapter will discuss all these aspects concerning DNA vaccine use for veterinary infectious diseases, focusing on veterinary clinical trials using in vivo GET as a DNA plasmid delivery method, explaining their mechanisms of action and also listing the already licensed veterinary DNA vaccines presented in the market.