OBJECTIVE: Recommendations from the Diabetes Control and Complications Trial (DCCT) indicate that adolescents with type 1 diabetes should be treated with intensive therapy involving multiple daily injections (MDI) of insulin or insulin pump therapy (continuous subcutaneous insulin infusion [CSII] to help obtain better metabolic control and prevent later complications. Interest has thus focused on insulin pump therapy to help adolescents meet this challenge. The purpose of this study was to examine responses to CSII and MDI in a large group of adolescents with established type 1 diabetes during a 12-month period and to determine whether either treatment regimen more favorably affected clinical and psychosocial outcomes. RESEARCH DESIGN AND METHODS: One-third of 75 youths aged 12-20 years who were candidates for intensive therapy chose CSII as their mode of treatment. Patients received intensive treatment and education as described by the DCCT investigators. Psychosocial data (e.g., quality of life, depression, self-efficacy, and coping) were collected at baseline and at 6-month intervals, and clinical data (e.g., HbA1c levels, adverse events) were collected every 4-6 weeks. RESULTS: Although both MDI- and CSII-treated adolescents initially exhibited improved metabolic control, this level of control was more difficult to sustain for 12 months in the MDI group (at 6 months HbA1c = 8.1, at 12 months HbA1c = 8.3), whereas average HbA1c levels in the CSII group continued to decrease during the 12 months of treatment (at 6 months HbA1c = 7.7, at 12 months HbA1c = 7.5). Despite lower HbA1c levels in CSII-versus MDI-treated patients, the rate of severe hypoglycemic events was reduced by almost 50% in the CSII group (P = 0.01). Self-reported questionnaires demonstrated that there was improvement in self-efficacy, depression, and quality of life in both MDI- and CSII-treated patients. Finally, adolescents using CSII found coping with diabetes to be less difficult than adolescents using MDI did. CONCLUSIONS: CSII is an alternative means to lower HbA1c levels and reduce the risk of hypoglycemia without adversely affecting psychosocial outcomes in adolescents with type 1 diabetes.