Foot-and-mouth disease virus (FMDV), in contrast to the antigen used for the production of FMD vaccine, can replicate in animals. As a result of infection the specific antibody to the viral structural proteins (SPs) and non-structural proteins (NSPs) of FMDV are synthesized. The laboratory diagnostic methods based on individual NSPs, e.g. 3D, 2C and 2B, as well as polypeptides, such as 3AB and 3ABC can be used for differentiation of infected and vaccinated animals (DIVA). This article presents the aim, principle, methods and results of applying DIVA strategy in the eradication of foot-and-mouth disease. The marker vaccines which enable differentiation between infected and vaccinated animals and appropriate ELISA serological tests for detection of antibodies to the NSPs of FMDV have been described. DIVA strategy makes it possible to reduce the economic losses and restore possibilities of international trade in animals and animal products. This strategy may be an alternative of the administrative “stamping-out” eradication method. The essential aim of DIVA strategy is realization of the so-called “vaccinate-to-live” policy, which is based on the principle that vaccinated animals exposed to FMDV will not transmit the virus. These animals are not epidemiologically risky, and therefore do not have to be eliminated. It is necessary to develop new vaccines and improve those already used as well as the application of reliable diagnostic tests to detect FMDV in vaccinated livestock populations.