1) The 77 patients with thyroid Ca. diagnosed with pathological findings from 1970 through 1976 are analyzed in histological type, metastatic involvement and preoperative thyroid scan and function test. Among 58 patients with Ca. 38 patients were performed by thyroid surgery only and 11 were treated with external irradiation after thyroid surgery and 2 with external irradiation only, 6 patients were treated with radioiodine after thyroid surgery and 1 with radioiodine ony. 2) Among 11 post-thyroidectomy patients treated with external irradiation, 9 have had local control after therapeutic dosage of irradiation and 1 with local recurrence and 1 with postoperative palpable necknode has had diappearance of a previous node after irradiation. 2 inoperative patients with Anaplastic types expired within 4 months after therapeutic dosage of external irradiation. 3) Among 5 inoperative patients treated with radiodine, 2 with recurrent Ca. and Rib metastasis showed improvement by X-ray r clinical finding after radioiodine treatment of 30 mci for each patient, one with lung metastasis showed moderate improvement of metastatic lesion by X-ray after radioiodine therapy of 40 mci and 2 with multiple bone metastasis revealed improvement by X-ray or clinical finding after Ⅰ-131 administration of 60, 120 mci for each patients. 2 postthyroidectomy patients with neck node metastasis by operative and pathological findings revealed local control after Ⅰ-131 therapy of 5, 30 mci for each one.