INTRODUCTION: Thyroid nodules are quite common in the population, however, distinguishing malignant thyroid nodules from benign ones constitutes a challenge. Ultrasonography (US) is a fundamental tool in the diagnosis of thyroid cancer. In 2017, the American College of Radiology released its recommendations for US analysis of thyroid, establishing the ACR TI-RADS, in an attempt to standardize indications for fine needle aspiration (FNA) between endocrinologists and radiologists. The Bethesda score obtained by FNA at one time provides subsidy for further surgery. The indication of FNA and the categorization of the nodule based on ultrasonographic characteristics, however, remains controversial. OBJECTIVES: To determine the correlation between thyroid US and FNA findings using ACR TI-RADS and Bethesda criteria in patients followed at HU-UFPI from January to June 2017. METHOD: Cross-sectional and observational study. The variables considered were sex, age, nodule size, ACR TI-RADS and Bethesda. For data analysis, means and percentages were obtained, and Chi-square, Student's t and Kappa tests were used. RESULTS: A total of 151 patients were evaluated, of which 94.7% were female. The mean nodule size was 2.1 cm and the mean age was 53.2 years. Among the variables, the size of the nodule was the most associated with the Bethesda classification. There was a positive association between the ACR TI-RADS and Bethesda methods. CONCLUSION: There was a correlation between the ACR TI-RADS ultrasonographic method and the Bethesda cytopathologic method. However, more studies are needed to determine the reliability of the ultrasonographic method.