Introduction. The basal dose of insulin, proportion of total daily insulin, and circadian variation during continuous subcutaneous insulin infusion (CSII) therapy among children with type 1 diabetes mellitus (T1D) have not been fully elucidated. Materials and Methods. A total of 45 childhood patients with T1D receiving CSII therapy at Pediatrics Department of Chang Gung Memorial Hospital between 2004 and 2012 were analyzed. Patients were classified according to Tanner stage. Results. HbA1c was significantly reduced in all Tanner groups within three months of CSII therapy (from 67 mmol/mol (8.3%) to 54 mmol/mol (7.1%), P < 0.05). The actual basal proportion of total daily insulin use was 34–40%. The circadian distribution of basal insulin differed markedly between the five Tanner groups. Basal insulin requirement was highest between 3:00 and 7:00 h in Tanner stages 1-2. In stages 3-4, a lower nocturnal basal insulin that increased gradually until daytime was noted. Adolescents (stage 5) displayed a high insulin peak between 6:00 and 11:00 h, and a smaller peak between 19:00 and 23:00 h. Conclusions. A smaller proportion of basal insulin to total daily insulin use, as well as varied circadian patterns of insulin use, characterized these children with T1D.