The aim of this study is to determine the proper initial dose adjustment when switching from multiple daily injections to continuous subcutaneous insulin infusion for type-1 diabetic pediatric patients. Our hypothesis is that the insulin adjustment varies depending on the pubertal status and the previous long-acting insulin used. Charts of 60 patients were reviewed. Data regarding insulin dose, type of insulin administrated, HbA1c, BMI, severe hypoglycemia and DKA events were collected during the previous year and after 6 weeks of pump therapy. In the prepubertal patients the reduction was 19% (26% if the previous insulin used was detemir). Pubertal patients experienced a decrease of 26%, and the detemir group 33%. The ratio long acting-basal/short acting-bolus insulin changed from 1.26 ± 0.84 to 0.93 ± 0.46 (P < 0.05). The total daily insulin dose needs to be decreased. Basal insulin constitutes 40-45% in prepubertal and 45-50% in pubertal patients. The reduction is different depending on the previous long-acting insulin used; being greater if the insulin is detemir.