The authors analyze criminological peculiarities of crimes committed by participants of ethnic criminal groups, their current state, and other factors on the basis of the conducted research. They state that organized criminal groups formed according to the ethnic criterion are distinguished by a certain «pattern in crime», a criminal specialization, and a unique internal structure. In the course of the research the authors established the tendency towards arranging the infiltration of criminal groups’ participants into governmental authorities, law enforcement agencies, and local self-government bodies by ethnic criminal groups’ leaders through the corruption of officials. The article represents only some of the criminological peculiarities of crimes committed by participants of ethnic criminal groups. The awareness of these peculiarities and directions of ethnic criminal groups’ activities is one of the necessary conditions to efficiently fight them.