OBJECTIVE: To compare the glucose variability associated with insulin glargine and NPH/Lente insulin used as the basal insulin component of a multiple daily injection (MDI) regimen in pediatric patients with type 1 diabetes. RESEARCH DESIGN AND METHODS: Continuous glucose monitoring data were collected from a subset of patients (n = 90) who agreed to use a continuous glucose monitoring system during an active-controlled, randomized, open-label study evaluating the safety and efficacy of insulin glargine and NPH/Lente insulin used with insulin lispro as part of an MDI regimen. RESULTS: Treatment with insulin glargine resulted in significant reductions in glucose variability as measured by the SD of glucose values (adjusted mean change from baseline to week 24: -13.4 mg/dl [-0.74 mmol/l]; P <or= 0.05), mean amplitude of glycemic excursion (-34.4 mg/dl [-1.91 mmol/l]; P <or= 0.0001), and M value (-9.6 mg/dl [-0.53 mmol/l]; P <or= 0.03). The corresponding reductions in glucose variability for NPH/Lente were not significant. CONCLUSIONS: Insulin glargine is associated with greater reductions in glucose variability than NPH/Lente insulin in pediatric patients with type 1 diabetes.