Dental caries, the disease that causes tooth decay, is infectious, and the mutans streptococci bacteria have long been identified as the primary disease-causing agents. Caries vaccines showed promising results in experimental studies; however, it remains far the effective use in humans due to political-economic and ethical issues. Progress towards practical vaccine development requires evaluation of candidate vaccines in clinical trials. Promising strategies of passive immunization also require further clinical evaluation. The purpose of this chapter is to review the literature on the main research projects aimed at developing caries vaccines.