Objectives: We aimed to reveal the effects of these two diagnostic methods on the decision of thyroidectomy by evaluating the preoperative ultrasonography (USG) and FNA results together and evaluating the treatment options and results. Methods: In this study,patient files pathology results and operative notes of 342 patients who had thyroid surgery in the General Surgery Clinic of Diskapi Yıldırım Beyazıt Training and Research Hospital were retrospectively analyzed.Preoperative USG, diameter and character of the dominant nodule, FNAB results, surgery types and postoperative pathology results were recorded. Results: one hundred thirty one of 342 patients (38%) presented as undetermined cytology. In our study, atypia of undetermined significance and follicular lesion malignancy rate were found to be 55.5% in the result of FNAB cytology. Conclusion: When deciding on the type of surgery, it would be more appropriate to consider the malignancy criteria in USG along with the result of FNAB. Different results will be more qualified with the increase of USG and FNAB experience.