The authors report their experience and surgical treatment of 440 patients with differentiated carcinoma of the thyroid (DCT) from 1970 to 1990 in the III Surgical Dept. at the University of Rome "La Sapienza". Considering 305 cases of papillary carcinoma, 103 Total Thyroidectomy (TT), 118 TT with Functional Regional Lymphadenectomy (FRL), 32 TT with Node-Picking, 51 TT with curative FRL and one TT with Radical Neck dissection were performed. In 135 cases of follicular carcinoma TT associated with Node-picking were performed on two patients, TT associated with FRL on 8 patients and TT associated with RND on 2 patients. Overall survival to 10 years was 90%; 98% for N- papillary carcinoma and 66% for N+ follicular carcinoma. There were no permanent recurrence of disease. Out of the patients who did not undergo cervical lymphadenectomy 30% developed temporary hypocalcemia; 53% (mediastinal lymphadenectomy) to 87% (FRL) of the patients submitted to lymphadenectomy developed temporary hypocalcemia with permanent hypoparathyroidism in 0.9%-23% of the cases. On the base of what has been observed by Pasieka and Grant, the Authors believe TT as the absolute solution for patients with DCT because it allows the removal of both the original tumor and the possible neoplasms in the residual gland tissue, and enables early identification of other metastases which can be treated efficaciously with I131.