Objective:To investigate the relation between calcification of nodular goiter and thyroid carcinoma.Methods :The clinical data of 1 024 cases of calcified nodular goiter, of which 544 cases (53.1%) were malignant, who were seen in our hospital during the past five years and were examined by highresolution ultrasonography preoperatively, were retrospectively reviewed.Results:There was no difference in the percentage of malignant calcified nodules between the male and female groups (58.3% and 52.5%, respectively；P＞0.05 ).There was a significant difference in the percentage of malignant calcified nodules between the patients of 45 years and older with those younger than 45 years (39.2% and 69.3%,respectively；P＜0.05).There was a significant difference in the percentage of malignant calcified nodules between the patients with solitary and multiple nodules (69% and 49.2%, respectively；P＜0.05).Moreover, there was a significant difference in the percentage of malignant calcified nodules between the group with microcalcification and the group with nonmicrocalcification (79.1% and 41.2%, respectively；P＜0.01).Conclusions:More than half the number of calcified thyroid nodules detected by ultrasonography have malignant pathological change, and once it is discovered that the nodular goiter has calcification,one should highly consider the possibility of malignancy. Microcalcification is a highly specific sign that predicts thyroid papillary carcinoma.When calcification appears in thyroid nodules or in regional lymph nodes, immediate surgery is required.