Veterinary vaccines are being used with increasing frequency in the United States to protect the health of animals. However, humans may be inadvertently exposed to these products by means of unintentional inoculation or other routes of exposure. The potential for both exposure and for adverse consequences secondary to exposure to veterinary vaccines may be growing. With the exception of brucellosis vaccines, there have been few reports of suspected or confirmed adverse events in humans associated with the use of animal vaccines, but it is unclear whether that is because few adverse events occur or because adverse events are not recognized and/or reported. Results of a search for relevant literature and of communications with health officials at governmental and private institutions suggest that enhanced efforts are needed to recognize and to prevent human illness associated with use of veterinary vaccines.