Abstract From 1958 to 1976, 910 patients with cold nodules of the thyroid underwent thyroid surgery (714 females, 196 males). Thyroid carcinoma was present in 202 patients (22.2 per cent) (149 females, 20.9 per cent; 53 males, 27 per cent). Rate of malignancy in an age group was greatest in patients older than seventy years (19 of 47 patients, 40.4 per cent) followed by patients twenty-one to thirty years of age (37 of 125 patients, 29.6 per cent); 90 per cent of all patients were from twenty-one to seventy years of age. Blacks had a lower rate of thyroid carcinoma than Caucasians. Data from the Cancer Surveillance Group also showed age-adjusted incidence rates in blacks in Los Angeles County to be lower than that of Caucasians.