Objective: To evaluate the clinical characteristics, course, and outcome of differentiated thyroid carcinoma (DTC) in pre-pubertal children compared with adolescents. Study design: The records of 10 pre-pubertal and 17 pubertal patients in whom DTC was diagnosed and who were observed in our tertiary pediatric endocrine clinic were reviewed. Extension of tumor at presentation, treatment modality, course, and outcome were analyzed. Results: A positive family history of DTC was more prevalent in the pre-pubertal group (P = .037). At diagnosis, they had a greater degree of extrathyroid extension (P = .012), lymph node involvement (P = .009), and lung metastases (P = .009). The extent of surgery was similar in both groups, whereas the weight-adjusted radioiodine (I131) ablative dose was higher in the pre-pubertal group (P = .004). During the median follow-up of 5 years, the overall survival rate was 100% for both groups, with no significant difference in evidence of residual tumor after initial therapy or the recurrence rate. Conclusion: DTC has a more aggressive presentation in pre-pubertal children. Rigorous initial surgical and I131 treatment, followed by thyrotropin suppression, was found to result in an outcome similar to that achieved in the pubertal group.