To assess long-term metabolic outcomes in children with diabetes mellitus that was diagnosed when they were <6 years old.A cohort of 66 children with diabetes mellitus that had a duration of at least 5 years and was diagnosed before they were 6 years old. Thirty-four children were treated at diagnosis with multiple daily subcutaneous insulin injections (MDI), and all these children, except 3, were switched to continuous subcutaneous insulin infusion (CSII; group A). Thirty-two children received CSII as initial treatment (group B).Hemoglobin A1c values were significantly lower in patients receiving CSII than MDI during all the 8 years of follow-up except one (year 1: 6.9% ± 0.9% versus 7.6% ± 1%, P = .011 ; year 4: 7.4% ± 0.8% versus 8.1% ± 0.9%, P = .006; year 7: 7.6% ± 0.5% versus 8.3% ± 0.8%, P = .001). The incidence of severe hypoglycemia was greatly decreased for the CSII group (9.8 versus 22.3 episodes/100 patient-years, P = .016). In group A, hemoglobin A1c values increased during the study period, and in group B, they increased only during the first 2 years and remained constant thereafter. Only 9.1% of patients did not use or abandoned CSII.CSII in children <6 years of age enables better long-term metabolic control and lowers the risk of severe hypoglycemia better than MDI, especially when initiated at diagnosis.