Introduction. Until recently, glycated hemoglobin (HbA1c) has not been studied in children with different types of diabetes mellitus (DM). With the development of molecular genetics, new types of diabetes have been diagnosed, including neonatal (ND) and maturity onset diabetes of the young (MODY), which usually require specific pathogenetic therapy, including sulfonylureas (SU), which improve glycemic control in patients with certain mutations. The aim of this study, which was conducted for the first time in Ukraine, was to analyze glycemic control in patients with different types of DM, including ND and MODY and changing their treatment after genetic testing. Materials and methods. We studied conducted the analysis of glycemic control in patients depending on the type of diabetes, namely: type 1 diabetes (n = 9282), type 2 diabetes (n = 23), ND (n = 16) with mutations KCNJ11, ABCC8 and MODY (n = 16) with mutations in HNF1A/HNF4A and ABCC8 genes. To confirm the nature of monogenic diabetes, targeting next-generation sequencing (tNGS) of all known neonatal and monogenic diabetes genes was performed. Results. According to the Register in 2018, in Ukraine the average age of children with type 1 DM was 11.5 ± 1.4 years, and the level of HbA1c was unsatisfactory (8.8 ± 2.01 %). The proportion of children who had ideal or optimal glycemic control (HbA1c