Backgrounds: Thyroid disease is very common, especially in women and the elderly. Thyroid ultrasound, as a first - line tool, is an imaging modality with outstanding capabilities such as being relatively simple, inexpensive, non - invasive, and repeatable for diagnosis of thyroid diseases, and can detect very small lesions. This study aims to determine the use of thyroid ultrasound with ACR-TIRADS 2017 classification in the diagnosis of thyroid nodules. Methods: A cross - sectional descriptive study was conducted in 169 patients undergoing thyroidectomy. All patients had been preoperatively performed thyroid ultrasound using a GE machine (LOGIQ S7 Pro, LOGIQ E9 ...) with a linear transducer frequency of 7.5 - 12 MHz. The ultrasound results using the 2017 ACR-TIRADS classification compared with pathological findings as the gold standard diagnostics. Results: Thyroid ultrasound using the 2017 ACR-TIRADS classification could distinguish benign and malignant thyroid nodules with the sensitivity of 97.9%, specificity 82.6%, positive predictive value 95.8%, negative predictive value 90.5%, and accuracy of 94.9%. The area under the ROC curve (AUC) of the ACR- TIRADS classification in the diagnosis of malignant thyroid nodules was 0.953 (p <
0.001). The cut - off point was selected as TIRADS 4. The area under the ROC curve (AUC) of the ACR - classification score of the armor particles was 0.967 (p <
0.001). The cut - off point is selected as 5 points. Conclusion: Thyroid ultrasound using the 2017 ACR-TIRADS classification is valuable in the differential diagnosis of benign and malignant thyroid nodules with high sensitivity and specificity.