To determine accuracy and intertest agreement of preoperative fine-needle aspiration cytology (FNAC) and intraoperative frozen-section analysis (FS) findings in thyroid surgery, and to assess the influence of intraoperative FS findings on decision making and the utility of FS in thyroid surgery. Retrospective analysis. The results of preoperative FNAC, intraoperative FS, and final histopathological analyses were taken from the histopathology reports. We calculated intertest agreement using the kappa statistic. Two-hundred fifteen patients who underwent primary thyroid surgery. All patients were treated by the same surgeon (S.J.W.). T he sensitivity and specificity of FNAC were 57.4% and 91.7%, respectively. The sensitivity and specificity of FS were 32.4% and 96.5%, respectively. The intertest agreement was poor (kappa = 0.17). In case of malignant FNAC findings, the FS result did not influence treatment decisions; in case of a malignant FS result on the background of a benign, indeterminate, or nondiagnostic FNAC finding, the FS result influenced treatment decisions in 88% of cases. Intraoperative FS did not give additional information in cases where a malignant neoplasm was predicted by the FNAC finding. In this setting, it led to conflicting results and did not contribute to correct decision making.