Sonograms in 84 patients with thyroid nodules were reviewed. The population consisted of 41 cases of adenoma, 21 cases of nodular hyperplasia, 8 cases of adenoma, 9 cases of cyst and 5 cases of thyroiditis. These sonograms were analysed in terms of their internal echogenicity, calcification, margin and peripheral halo. Calcification was discovered in 3 cases of benign disease and 3 cases of carcinoma. The margin was well defined in 70 out of the 76 cases of carcinoma. The margin was well defined in 70 out of the 76 cases (92%) with benign disease and 2 out of the 8 cases (25%) with carcinoma. A peripheral halo was visible in 51 out of 76 cases with benign diseases and 2 out of the 8 cases (25%) the carcinoma. Sonography was not useful in the tissue characterization of thyroid nodules.