The article is devoted to the study of cohesion of servicemen as one of the important factors determining the nature of interaction in the military collective. The author emphasizes that the cohesion of servicemen largely depends on: psychological compatibility of servicemen, combination of their psychological qualities, which would allow them to participate peacefully in joint combat activities, the basis of which is correspondence of individual temperamental properties and socio-psychological compatibility of wrestlers, which reflects their professional and moral qualities. According to the author, compatibility is one of the most important conditions for group cohesion and effectiveness of activities in combat conditions. It was noted that military psychologists and unit commanders should pay great attention to the recruitment of small military units based on three levels of psychological compatibility of military personnel: psychological (compatibility of temperaments); professional (compatibility of ideas about military activities); value-orientated (consistency of value orientations of servicemen).