This study was aimed to 1) assess glycemic control in a group of 61 children and adolescents with type 1 diabetes mellitus (DMT1) based on the results of conventional self-monitoring of blood glucose (SMBG) and continuous glucose monitoring (CGM), 2) evaluate the usefulness of CGM in making changes in therapy in order to improve its results. At the beginning of the study, CGM revealed hyperglycemias in all patients and hypoglycemias in 93%. SMBG alone was not able to detect all those glycemic excursions. 100% of patients experienced postprandial hyperglycemias and approximately 85% asymptomatic hypoglycemias, including nocturnal episodes. Based on the results of the first CGM modifications in diabetes therapy were introduced in all patients. After the 3-month follow-up HbA1c decreased significantly in the entire studied group (7,7 vs. 7,3%) without an increase in total daily insulin dose. Second CGM performed at that time revealed significantly fewer hyperglycemias of shorter duration. The number of hypoglycemias did not change throughout the study, but their duration increased significantly. However, there was no increased risk for severe hypoglycemia. The author concludes that intensive insulin therapy, particularly pump therapy using rapid acting analogs is a safe and effective regimen for children and adolescents with DMT1. The routine metabolic control in this age group should be extended with periodic monitoring of daily glucose profiles using CGM.