Background: Pediatrics thyroid cancers tend to be at more advanced stages at the time of diagnosis and have higher frequency of recurrences than adulthood thyroid cancers. The aim of study was to evaluate clinical characteristics and outcome between children and young adults patients with Differentiated Thyroid Cancer (DTC) treated in our hospital. Material and Methods: The medical records of 144 patient with DTC who underwent thyroid surgery followed by radioiodine and thyroid hormone suppression were retrospectively reviewed. Subjects consisted of 43 patients who were younger than 21 years old, and 101 young adult patients (older than 21 years old but younger or equal to 40 years). The clinical characteristics and outcomes were analyzed and compared, then Recurrence Free Survival (RFS) was evaluated using Kaplan-Meier Methods. Results: Female has higher tendency to have thyroid cancer than male (p = 0.006). Based on histopathology report, classic papillary thyroid cancer is the most common cancer type in children than young adult. However, there was no significant difference between two groups regarding thyroid cancer size and multifocality (p=0.815 and p=0.370). The risk of recurrent ratio of children to young adults is 3.88 (95% CIÂ 1.38; 10.91). Similar result trend is shown for sex type, histopathology type, number of nodules, surgical technique and metastasis parameters. (adjusted HR =Â 7.91, 95% CI 2.11; 29.67). Conclusions: Differentiated Thyroid Cancers in children show more aggressive behavior compared to young adult patients.