Objectives: To review our institutional experience and to analyze the clinical decisions made after a cytological diagnosis of atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS). Study Design: This is a retrospective review of all thyroid fine-needle aspiration (FNA) cytologies performed in the Hospital Clínico San Carlos (Madrid) between 2010 and 2014. Results: One hundred thirty thyroid FNA were categorized as AUS/FLUS (5%). One hundred six (81.5%) patients were women, and the mean age was 59 years. In 61 patients a repeated FNA was performed (46%). Fifty-five nodules were treated surgically (42.3%), with a histopathological diagnosis of nodular hyperplasia in 36 cases (65%), adenoma in 11 (20%), and carcinoma in 8 (14.5%). In the group of nonsurgical patients (n = 75), a repeated FNA was performed in 43 (57.3%) cases. We found no statistically significant association between sex or age and clinical management (p = 0.13 and p = 0.31, respectively). Conclusions: Clinical management after an AUS/FLUS FNA diagnosis is erratic and does not match standardized management protocols. The AUS/FLUS classification has not led to new diagnostic tests in a relevant percentage of patients. The implementation of consensual institutional strategies could lead to better management of these cases.