Objective: To review our experience with insulin dosing during the conversion from multiple daily injections to continuous subcutaneous insulin infusion (CSII) for children and adolescents with type 1 diabetes mellitus. Study design: The charts of 65 children who started CSII from January 1998 to April 2000 were reviewed. Data regarding insulin dose and hemoglobin A1c levels were collected from the prepump visit and first (at 1 to 2 months) and second (at 3 to 6 months) visits after being placed on pump therapy. Results: Pubertal patients had a decrease in total insulin dose taking CSII; prepubertal patients had little change (−18 ± 3.5% vs −1.7 ± 5%, P =.01). On CSII, the basal insulin dose comprised 40% to 45% of total insulin in both prepubertal and pubertal patients. Maximal basal rate in prepubertal patients occurred from 9 PM to 12 AM and in pubertal patients from 3 AM to 9 AM and from 9 PM to 12 AM. Conclusion: Guidelines established for CSII dosing in adults do not necessarily apply to children. The total daily insulin dose needs to be decreased in pubertal patients but may remain unchanged in prepubertal patients. The basal rate comprises 40% to 45% of the total daily insulin dose, and the timing of maximum basal rates is likely to occur in the late evening hours in prepubertal children. (J Pediatr 2002;140:235-40)