Mastocytosis is a rare hereditary disease with a complex pathogenetic process. The causes of the disease development are not established, it is more often registered in childhood, the pathological process involves the skin, bone marrow, spleen, liver, lymph nodes and gastrointestinal tract. Insufficient knowledge of the epidemiological features of mastocytosis in children determines the relevance of the study of the problem. Purpose of the study was to investigate the frequency of mastocytosis disease registration and skin malformations in the pediatric population of Moscow. Material and methods: The data of the form №12 of the federal statistical observation "Information about the number of diseases registered in patients living in the service area of the medical organization" and the Appendix "Dermatoses" developed by the staff of the " Moscow Scientific and Practical Center of Dermatovenereology and Cosmetology» were used in the work. To calculate extensive indicators, we used the data from the Federal Service for National Health Statistics № 12 Information on the number of diseases registered in patients living in the service area of the medical organization" for 2019, 2020, 2021 and 2022. To calculate the level of morbidity in intensive indicators per 100 thousand population, data on the population of Moscow for the period 2019-2022 were used. The paper presents the results of a single-center epidemiological study using statistical, analytical research methods, content analysis, current observation, desk research for the period from 2019 to 2022. Due to the infrequent registration of the investigated problem, a continuous retrospective study on an open cohort was conducted. Data analysis was performed using Excel statistical software package from Microsoft Office 365 package. Results: The analysis of detectability of congenital anomalies (malformations) of skin development and incidence of cutaneous mastocytosis among the pediatric population of Moscow for the period from 2019 to 2022 has been carried out. The results of the research show that annually in the pediatric population the number of detected cases of skin malformations increases to 20.0% and more, the cases of detection of cutaneous mastocytosis have increased by 2.2 times. The registration of congenital anomalies (malformations) of the skin increased 4.8 times during the study period. In the structure of detected anomalies (malformations) of skin development in childhood, the growth of cutaneous mastocytosis can be traced in dynamics. Conclusion: The incidence rate of cutaneous mastocytosis in children increased 4.6-fold over the entire study period (from 3.6 in 2019 to 16.6 per 100,000 of the corresponding population in 2022).