Background: The aim of the present study was to evaluate the presentation, clinical course and outcome between children and young adults with differentiated thyroid cancer (DTC) treated in our hospital. Materials and Methods: The medical records of 145 patients with DTC who underwent surgery followed by radioiodine and thyroid hormone (TSH) suppression were retrospectively reviewed. The follow up was between January 2006 and June 2012. These patients consisted of 38 children (age${leq}18y$) and 107 young adult patients (age${leq}30y$). The clinical characteristics and outcome were analyzed and compared, and the progression-free survival (PFS) was evaluated using the Kaplan-Meier method. Results: At initial diagnosis, a greater degree of extra thyroidal extension was found in children than adults patients (p<0.001). However, there was no significant difference between the two groups with regard to the tumor size and the presence of lymph node or distant metastasis (p=0.172, p=0.050 and p=0.068, respectively). The extent of surgery and the cumulative or mean dose of radioiodine were similar in both groups. During the follow up, the overall survival rate was 100% for both groups, and the PFS rate was similar in children and in young adults group (log rank test, ${chi}^2$=0.126, p=0.723). Conclusions: In comparison to the young adult patients, DTC in children presents with more aggressive behavior, but outcomes are similar between the two groups after the intensive management of surgery followed by radioiodine and TSH suppression therapy.