At the University of California Hospitals a study has been made of the 390 patients with thyroid carcinoma who were observed in the 40-year period between 1920 and 1959. Thyroid carcinoma was found in both lobes at the time of the "initial operation" in 19 per cent of these patients, and regional lymph node metastases were reported at one time or another in 42 per cent. These data warrant a more radical surgical approach to thyroid carcinoma. During the past fifteen years, therefore, the majority of such patients at the University of California have been treated by more radical forms of thyroidectomy. The rate of local recurrence in the thyroid area was significantly lower in patients treated by total thyroidectomy than in those treated only by unilateral subtotal lobectomy. Cumulative survival rates were higher for patients with papillary carcinoma than for those with follicular carcinoma, and the survival rates for patients with papillary or follicular carcinoma were higher than for those with anaplastic carcinoma. Thyroid carcinoma is a lethal disease despite prolonged survival of many of the patients. Eventually 19 per cent of the 390 patients died of thyroid carcinoma (papillary 11 per cent, follicdar 33 per cent and anaplastic 76 per cent).