Purpose:There are relatively few results from studies on nodular Hashimoto's thyroiditis. In addition, some Hashimoto's thyroiditis patients present with irregular symptoms, making the distinction from malignant thyroid nodule difficult. Therefore, we performed analyses on ultrasonographic findings of nodular Hashimoto's thyroiditis. Methods: A retrospective follow-up study was performed on 76 patients (88 nodules) diagnosed with Hashimoto's thyroiditis after undergoing fine needle aspiration biopsy from January 2009 to December 2010. A frequency analysis was performed to investigate the most common ultrasonographic findings of nodular Hashimoto's thyroiditis. In addition, patients were divided into two groups based on the presence or absence of extensive Hashimoto's thyroiditis on the parenchyma, and ultrasonographic findings were compared and analyzed for nodules in each group. Results: The study was performed on 76 patients and 88 nodules. The majority of nodular Hashimoto's thyroiditis were found to be solid on ultrasonography, and echogenicity was mostly hypoechoic, with prominent hypoechoic findings being more common. Most nodules did not have a rim surrounding the margins, and absence of accompanying calcification was also noted. The comparison and analysis of ultrasonographic findings of two patient groups that were divided based on the presence or absence of Hashimoto's thyroiditis across the parenchyma, revealed no significant difference.