OBJECTIVE To describe a 2-year follow-up of A1C outcomes of a self-regulation intervention for youth with type 1 diabetes. RESEARCH DESIGN AND METHODS A total of 81 youths with type 1 diabetes ages 11–16 years were randomized to usual care versus a diabetes personal trainer intervention consisting of six self-monitoring, goal-setting, and problem-solving sessions with trained nonprofessionals. A1C data were obtained from medical records 2 years postintervention, and ANCOVA adjusting for age and baseline A1C was conducted. RESULTS An overall intervention effect on A1C (8.93% control vs. 8.43% intervention; F = 8.24, P = 0.05) and a significant intervention-by-age interaction (F = 9.88; P = 0.002) were observed, indicating a greater effect among older than younger youths. Subgroup analyses demonstrated no treatment group differences among pre-/early adolescents but a significant difference in A1C among middle adolescents (9.61% control vs. 8.46% intervention; F = 7.20, P = 0.011). CONCLUSIONS Findings indicate maintenance of intervention effects on A1C observed at 1-year follow-up.