There have been many new promising approaches to developing human vaccines against tuberculosis (TB). Advances in gene and antigen identification, availability of genome sequences, a greater understanding of immune mechanisms in resistance to TB, the development of adjuvants and delivery systems to stimulate T-cell immunity, and increased funding from public and private agencies are some of the reasons for progress in this area. Dozens of vaccine candidates have been tested in animal models in recent years, and several of these are poised to move into clinical trials in the next several years. Thus, there is renewed optimism for the potential of developing new and improved TB vaccines.