Thyroid ultrasound (US) is a key examination for the man- agement of thyroid nodules. Thyroid US is easily accessible, noninvasive, and cost-effective, and is a mandatory step in the workup of thyroid nodules. The main disadvantage of the method is that it is operator dependent. Thyroid US as- sessment of the risk of malignancy is crucial in patients with nodules, in order to select those who should have a fine nee- dle aspiration (FNA) biopsy performed. Due to the pivotal role of thyroid US in the management of patients with nod- ules, the European Thyroid Association convened a panel of international experts to set up European guidelines on US risk stratification of thyroid nodules. Based on a review of the literature and on the American Association of Clinical Endo- crinologists, American Thyroid Association, and Korean guidelines, the panel created the novel European Thyroid Imaging and Reporting Data System, called EU-TIRADS. This comprises a thyroid US lexicon; a standardized report; defini- tions of benign and low-, intermediate-, and high-risk nod-ules, with the estimated risks of malignancy in each catego- ry; and indications for FNA. Illustrated by numerous US im- ages, the EU-TIRADS aims to serve physicians in their clinical practice, to enhance the interobserver reproducibility of de-scriptions, and to simplify communication of the results.