This study analyzed the features of the nodules requiring a fine needle aspiration, which were found in thyroid ultrasonography of the employee health check-up examinees. Based on the fine needle aspiration results, over 1 cm nodules or those implying malignancy on the ultrasonography were categorized into the 1st group. Whereas, regardless of the size the fine needle aspiration results implying malignancy on the ultrasonography were categorized into the 2nd group. In the 1st group, 15.8% were malignant, and in the 2nd group, 28% were malignant. The findings implying malignancy were statistically significant. However, even though the nodules were larger than 1 cm, when the nodules were not accompanied by a high risk factor and showed a spongiform structure in the ultrasonographic results, most of them were benign, and a fine needle aspiration was not required. The ultrasonographic findings are important rationales in making a decision on whether or not a fine needle aspiration is required for thyroid nodules. Currently, the fine needle aspiration for thyroid nodules is commonly performed when the size of the nodule is larger than 1 cm, even though it has a spongiform structure, to relieve the patient's anxiety. However, if ultrasonographic findings of thyroid are correctly understood in differentiating malignant from benign nodules, unnecessary fine needle aspiration can be avoided.■ keyword :|Thyroid|Fine Needle Aspiration|Spongiform|