The purpose of the report is to inform Russian specialists in the field of child mental health about the international Diagnostic Classification of Mental Health and Developmental Disorders in Infancy and Early Childhood DC:05: its purpose, age focus, structure and content of diagnostic axes, as well as about the steps which were undertaken by domestic experts to popularize it in Russia. It is shown that this diagnostic classification was developed by leading foreign experts in the field of mental health of children, is based on the analysis and generalization of a large amount of clinical data from around the world and covers a wide range of mental disorders in children during the first five years of life. The interdisciplinary focus of DC:05 is emphasized, as well as its consistency with the DSM-5 and ICD-10 systems and the ability to supplement them, taking into account the bright age-specific disorders. The fact is noted that this diagnostic classification is practically unknown among Russian specialists. The report briefly highlights the results of the research activities of the interdisciplinary research group of the Scientific Center for Mental Health (Moscow), carried out in the period from 2002 to 2017. and aimed at analyzing the diagnostic approaches proposed by the classification and testing them on Russian samples. The release of the Russian edition of DC:05 was announced, carried out in 2022 by the non-profit organization Caritas Social School (St. Petersburg) with the official consent of the DC:05 developer company and in cooperation with the Faculty of Psychology of St. Petersburg State University, and the accompanying DC:05 orientation course, developed by this team for Russian child mental health professionals.Keywords: infancy, early childhood, mental disorders, diagnostic classifications, DC:05