The object of study – the abnormal social phenomenon of social development – mass children's homelessness, its level and distribution forms, participation of the public and power state structures in its overcoming. The purpose of study is objective finding-out of optimum forms of interaction of the state and the public in the field of operatively-organizational and socially-preventive activity on elimination of mass homelessness of children in USSR, scientifically-historical reconstruction of features of formation of structure and performance of preventively-rehabilitation functions by a society «Friends of children», generalization of historical experience of struggle with асоциальными the social development phenomena. The methods: structurally-system, chronological, descriptions, statistical, dynamic, comparative. The practical value of the work: theoretical generalizations, an actual material, research conclusions can be used not only for a writing of scientific and popular works on a social history of Ukraine of 20-30th ХХ century And also for preparation of regulatory legal acts on the important problems of a family and youth, for improvement of work of boarding school-type children’s establishments and preventive maintenance of children's homelessness. Results of research will promote a scientific substantiation of a state policy in the field of socially-right protection childhood, actualization of ideas of revival of public organizations for overcoming of homelessness of children, prevention deviation forms of their social behavior. Dissertation is the first research on a history of formation and functioning of public organization - company "The Friends of children", its role and place in overcoming of mass homelessness of children in USSR of 1920th - 1930th. The scientific literature of 1920th, brochures and articles of 1930th, monographs and dissertations of the historians of 1950th - 1980th, modern historiography are analyzed. Is established, that the activity of All-Ukrainian company "The Friends of children" is mentioned partially in separate works, and system research does not exist. The features of formation of organizational structure of the centres, central bodies of management, relation of official establishments with public organization for the sake of overcoming a children homelessness are investigated, its reasons and level in USSR of 1920th -1930th are revealed, the specificity of education-propaganda activity of the centres, realization by them of operative-preventive measures and social-rehabilitation functions of children's establishments of boarding school type is found out. Current opinion in historiography of 1970th - 1980th the statement, that mass homelessness of children in USSR was overcome in 1932, dethroned.
