© 2021, Italian Society of Medical Radiology.Introduction: Thyroid ultrasonography (US) is the first-step noninvasive and easily accessible diagnostic method widely used in the detection and characterization of nodular thyroid disease. We aimed to develop a TI-RADS, which is easy to apply and only relies on the counting of suspicious criteria. In order to measure the reliability of the system, we investigated its correlation with fine needle aspiration biopsy (FNAB) and post-surgery histological results. Materials and methods: In this prospective study, 242 patients who had undergone FNAB with simultaneous cytopathologist in the radiology department between April and August 2016 were analyzed. Before FNAB, the thyroid gland was re-evaluated with US, and TI-RADS classification was made. Demographic characteristics, family thyroid cancer history and radiotherapy history to the neck region were noted. Results: Of the 242 patients, 17.3% were male (42 males/200 females). US-guided FNAB was applied to all patients. Mean age was 50 ± 13 years (min: 19, max: 82). Both FNAB and final post-surgery histology results showed that sex and age were not statistically significantly associated with malignancy (p = 0.193) TI-RADS criteria and FNAB results revealed a statistically significant association between irregular contours, the state of anteroposterior diameter being longer than transverse diameter, microcalcifications, marked hypoechogenicity, and malignancy (p < 0,05). Thirty patients were TI-RADS ≥ 4, 206 patients were TI-RADS ≤ 3 and there was a significant correlation between TI-RADS and Bethesda classification (p = 0.001). In addition, statistically significant associations were found between malignancy and family history of thyroid cancer (p = 0.035) and radiotherapy history to the neck region (p = 0.01). Conclusion: TI-RADS system after nodule identification is based only on the counting of suspicious criteria. It will be safe and effective to recommend follow-up with low score TI-RADS, benign characters and insufficient FNAB results, and thus, unnecessary thyroidectomy operations will be prevented. It will be easier for surgeons to recommend surgery and persuade the patients for it when patients have high TI-RADS scores. TI-RADS has high power in detecting malignancy by recommending biopsy of suspicious nodules.