Background: The use of ultrasound aids in the identification of thyroid nodules, but it is still crucial to determine whether or not they are problematic using non-invasive methods. Aim of work: To evaluate validity of TIRADS in diagnosis of nature of thyroid nodules. Subjects and methods: A cross sectional study was conducted on 95 nodules derived from thirty patients in radiodiagnosis department in Zagazig University hospital from February 2018 to June 2019. All patients underwent complete history taking, full clinical examination, ultrasonographic evaluation of thyroid gland and Fine needle aspiration cytology (FNAC) for solitary nodule or the most suspicious nodules in patients with multinodular goiter and then smears were pathologically assessed. Results: About 73% of patients were females with mean age 46 years. Out of the ninety-five nodules, fifty were assesses using US-guided FNAB. Ten nodules were malignant. Papillary carcinoma was the most common accounting for seven nodules. Thyroid Imaging Reporting and Data System (TIRADS) 3 was the most commonly encountered category accounting (42%) while The different TIRADS categories were confronted with the results of pathology and the risk of malignancy were Compared with benign nodules, significantly higher percentages of malignant nodules wee solid, hypoechoic, with irregular margins, taller-than-wide morphology, with microcalcifications, markedly hypoechoic or associated abnormal cervical lymphadenopathy. Tab and T5 predict malignant nature of nodule with sensitivity 90%, specificity 95%, and 95% accuracy. Conclusion: Russ' modified TIRADS classification is reliable in both stratifying nodular thyroid disease based on the risk of malignancy and predicting thyroid malignancy.