This retrospective study assessed 17 DM1 pediatric patients (15.76 +/- 4.5 years) submitted to 72 h continuous glucose monitoring system (CGMS) (Medtronic, CA). The aim of this study was to evaluate the accuracy of CGMS in children and adolescents with type 1 diabetes mellitus (DM1) and the efficacy of this method to detect unrecognized hypoglycemia in this population. It were analyzed capillary glycemia (CG) and CGMS sensors value; glycemic excursions; postprandial hyperglycemia; unrecognized hypoglycemia; complications and therapeutic management after CGMS. A1c levels were measured at the start and after 3 months of the study. Correlation coefficient during hypo, hyper, and normoglycemia and sensitivity/specificity was determined. The mean CG values were 213.8 +/- 63.4 mg/dl vs. 209.7 +/- 52.5 mg/dl by sensor, with statistical significance by Pearson's correlation (p < 0.001). There was no difference between CGMS and CG value in order to detect glycemic excursions (p = 0.32). The postprandial hyperglycemia and unrecognized hypoglycemia was detected in 66.7% and 56.2% of this patients, respectively. The correlation coefficient during hypoglycemia presented no statistical significance by Pearson's correlation (p = 0.29) vs. during hyperglycemia (p = 0.001). The CGMS sensor presented low sensitivity (63.3%) to detect hypoglycemia. This data showed important decreased level of A1c in this population 3 months after CGMS with statistical significance (p = 0.03). The CGMS showed to be a very safe method, well tolerated, with high accuracy in glycemic values and low complications rate. This results suggest that CGMS is a good method to identify postprandial hyperglycemia, to improve metabolic changes in therapeutics with significant impact in A1c of diabetic pediatric patients. This data confirmed the low sensitivity of CGMS to detect unrecognized hypoglycemia in pediatric DM1 patients.