The control of bovine tuberculosis remains a significant problem in the United Kingdom, especially in the south west of England where the rising prevalence of the disease is attributed to a reservoir of Mycobacterium bovis infection in badgers. The possibility of controlling the disease by the vaccination of cattle has been unpopular with veterinarians largely because of the potential compromise of existing diagnostic tests. However, the vaccination of badgers to reduce the risk of transmission to cattle is an attractive option and has now been adopted as a potential control strategy. Recent research has led to important advances in the molecular genetics of mycobacteria and in the understanding of protective immune responses. These advances mean that it may be feasible to design and develop effective mycobacterial vaccines. This review summarises the current understanding of protective immunity against M bovis infection and discusses the possible strategies for the development of vaccines.