In a sequence of 1,020 autopsies, all thyroid glands were thoroughly examined during a two-year period. Fifty-seven percent of the thyroid glands had no gross or histologic changes; approximately 22% were more or less goitrous. In 63 of 1,020 (6.2%) thyroid glands, a clinically latent carcinoma was detected. The greatest diameter of tumors measured microscopically ranged between 0.5 and 10.5 mm. Sixty-nine percent of the carcinomas were found by excision of a local change of tissue visible through close examination by the naked eye. All but one carcinoma were of papillary type, the one exception being a C-cell carcinoma. Multicentricity was found in 46% and regional lymph node metastases in 14%. There was no significant predilection of sex or age. It was concluded that these tumors have no propensity to increase to a clinically apparent thyroid disease.