Objective: To study the relation of age and clinicopathologic pattern to the aggressiveness of thyroid cancer cases and the treatment results of patients from western region of Saudi Arabia with differentiated thyroid carcinoma referred for treatment in King Abdulaziz Hospital and Oncology Center, Jeddah, Saudi Arabia. Methods: Retrospective review of 174 patients with differentiated thyroid carcinoma and analysis of the clinicopathologic characteristics, age correlation to different risk factors, treatment protocol and results were performed. Results: Analysis of the clinicopathologic pattern showed no statistically significant difference between patients in the different age groups except for extrathyroid extension and lymph node involvement. Patients older than 45 years had a statistically significant lower incidence of nodal involvement and a higher rate of extrathyroid extension (<0.02). In this study, we used a high dose method (Radioiodine-131 dose 75 - 100 mCi) for thyroid remnant ablation after thyroidectomy (total or near total) in 134 patients. An Iodine-131 dose of 200 mCi was used in 8 patients with distant metastases. In 24 patients with radioiodine-avid cervical lymph nodes and six patients with a gross residual tumor, an Iodine-131 dose of 150 mCi was used. For the whole study group, the 5-year overall survival and disease-free survival were 96% and 88%. Conclusion: Despite the fact that differentiated thyroid carcinoma is among the most curable cancer some patients are still at high risk for recurrent and increased mortality.