Aim: We hypothesized that the estimated risk of malignancy for atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) is higher than anticipated in Bethesda system. Therefore, we analyzed the actual malignancy risk of repeated AUS/FLUS diagnosis of thyroid fine-needle aspiration biopsies (FNAB). Materials & methods: We reported retrospective analyzes of 112 cases with repeated AUS/FLUS diagnosis among 10,769 thyroid FNABs. The histologic follow-up were evaluated in the study. Results: 112 cases with a repeated diagnosis of AUS/FLUS, histologic follow-up revealed 56 (50%) benign, 46 (41%) malignant and ten (9%) well-differentiated tumors of uncertain malignant potential outcome. Conclusion: The malignancy risk of AUS/FLUS category in thyroid FNABs was higher than anticipated in Bethesda system. Therefore, the management strategy of AUS/FLUS should be revised.