Emergence as a little discussed bioecological phenomenon in infectious pathology, the most important in the current period, its actual significance, nature, causes in general terms and in relation to the situation in the Russian Federation is considered. In this context, the main provisions, problems and non-trivial phenomena in the epizootology of emergent infections, economically and socially important for the country, are presented - African swine fever, rabies, foot and mouth disease, avian flu, nodular dermatitis and anthrax. Most emergent infections of domestic animals and humans are of zoogenic origin. These are mainly (more than 70%) diseases of the wild animals - ungulates, carnivores, primates, rodents, birds, bats, representatives of other mammals and non-mammal groups, the causative agents of which come from natural zoonotic pools. It is obvious that the achievements of human civilization over the past decades are the driving forces for the emergence and spread of emergent diseases although indirect, but decisive. The most demonstrative evidence of this conclusion is an infection associated with bats. The movement of people, tourism and trade, hydropower, agrarian expansion, deforestation, amelioration, unrestrained humanization and urbanization of territories, with unpredictable consequences, perturb the prevailing relations between representatives of the animal world and the environment. One of the subjective elements of the phenomenon is the large-scale traffic of wild animals from biological invasions, artificial introduction into new territories and trade in living goods. At the same time, the emerging problems of protecting animals and humans from new highly dangerous, transboundary and other infections are difficult to solve from a social and mental point of view - they compromise the overall socio-economic, scientific and technological progress, focusing on its negative aspects and internal conflict with at least the well-being and consistency of the environment.