The aim of modern insulin therapy used in the treatment of type 1 diabetes mellitus is to mimic the physiological secretion of insulin in order to ensure stable normoglycemia while maintaining the greatest possible comfort of life for diabetic patients. New ultra-fast insulin analogs that can be administered immediately before a meal contribute to the improvement of postprandial glycemia and the quality of life of patients. We presented two cases illustrating the effectiveness and safety of the use of an ultra-fast-acting insulin analog in the treatment of postprandial hyperglycemia in children with type 1 diabetes.