Ninety patients from a demographically well-defined area of, on an average, 243,000 inhabitants were surgically treated for thyroid carcinoma during an 18 year period. Sixty-five of the patients had papillary carcinoma, 20 follicular carcinoma, 4 medullary carcinoma, and 1 anaplastic carcinoma. Seventy-eight patients were operated on for cure, and among them, 23 had total thyroidectomy and 55 partial thyroidectomy. Additional therapy with thyroxine was given to all patients postoperatively. None of the patients treated for cure died from thyroid carcinoma at follow-up 2 to 20 years after diagnosis. One of 42 patients (2.4 percent) primarily treated for cure with lobectomy for papillary carcinoma had local recurrence in the thyroid bed which was excised successfully. No patient treated for cure of follicular carcinoma had local recurrence. All verified recurrences except one were diagnosed within 5 years of primary operation. We conclude that local recurrence after procedures less than total thyroidectomy that are considered to be curative is unusual provided that thyroxine is given postoperatively. Thus it seems that the reported high rates of microscopic carcinoma in the contralateral lobe in patients with unilateral cancer have little clinical significance. A conservative approach in most patients with localized thyroid carcinoma is indicated because it reduces the risk of postoperative complications.