Twenty-six cases of patients with thyroid cancer surgically treated during the past 5 years, which occupied 22 % of all in-patients(118 cases) with various thyroid diseases, were surveyed clinically and pathologically . The results are as follows:1) The incidence of thyroid cancer occupies 37.7 % of a total of both clinical non-toxic nodular and clinical thyroid tumors, 16.7 % to the clinical non-toxic nodular goiters and 85.7 % to the clinicalthyroid tumors. 2) The incidence of malignant adenoma is 20% of all adenomas in the clinical nodular goiters. 3) Histologically is the thyroid cancer papillary type in over 50 %. 4) The thyroid cancer is prevalent in female(4.25 to 1) and in third decade of life. 5) The average duration of symptom before presentation is 6.8 years. 6) The site of origin on the thyroid is variable. 7) The detectable metastases are of 50 % of all cases, mostly in cervical lymph node and occasionally to bones. In malignant adenomas it is evident to be metastasized in late stage. 8) In the treatment of thyroid cancer the prompt surgical removal is inevitable, and the prophylactic resection of nodules in the thyroid is also recommended in malignant adenomas both subtotal and contra--lateral lobectomy as well as postoperative irradiation would be the choice of treatment.