Diabetic children treated with intensive insulin therapy are showing a dangerous increase in severe hypoglycemic episodes. The Continuous Glucose Monitoring System (CGMS) allows glycemic profiles to be monitored over a 72-h period. The aim of the present study was to evaluate whether this system is sufficiently sensitive to detect asymptomatic hypoglycemia, and to determine if its periodic application would help to minimize the hypoglycemic risk in children with type 1 diabetes mellitus (T1DM). Twenty-seven T1DM children (age range 6-13.1 years) were enrolled in the study. The sensor was inserted subcutaneously in each patient and the standard four or five registrations of capillary glycemia per day were performed. Eighteen patients continued in the study and the glucose sensor was again inserted after a 6-week interval. At the beginning and end of the study, fructosamine, glycosylated hemoglobin (HbA(1c)), median glycemia, number and duration of hypoglycemic events and insulin requirement were evaluated. A significantly higher number of asymptomatic hypoglycemic events was revealed by CGMS in comparison with the standard system (3.6 +/- 2.3 vs 0.7 +/- 0.9; p < 0.0001). In patients who continued in the study, insulin therapy adjustments reduced the incidence of hypoglycemic events (2.5 +/- 1.7 vs 3.9 +/- 2.2; p < 0.05). At the 6-week point, the fructosamine level was reduced (330 +/- 30 vs 349 +/- 24 micro mol/l; p < 0.05). The CGMS is a useful device not only for detecting unrecognized hypoglycemia, but also for modifying insulin therapy in order to reduce hypoglycemic events. The system appears to be useful in avoiding long exposure to hypoglycemia. Copyright 2002 John Wiley & Sons, Ltd.