Vaccination continues to be the main approach to protecting animals from infectious diseases. Until recently, all licensed vaccines were developed using conventional technologies. However, the introduction of modern molecular biological tools and genomics, combined with a better understanding of not only which antigens are critical in inducing protection, but an appreciation of host defences that must be stimulated, has opened a new opportunity to develop safer and more effective vaccines. The authors describe the current and future trends in vaccine development and stress that in addition to identifying and producing the protective antigens, it is critical to formulate and deliver these vaccines appropriately to maximise the potential of modern advances in pathogenesis and vaccinology.