Fine-needle aspiration (FNA) is the first-line and a cost-effective examination method of nonfunctional thyroid nodules. Acute transient thyroid swelling after an FNA is a rare complication, and to date, only 14 cases have been reported in the English literature. Herein, we report a case of a 26-year-old woman with acute transient thyroid swelling, which occurred after an ultrasound-guided FNA of a thyroid nodule. Although the patient had undergone an FNA without complication 2 years previously, the second FNA caused acute thyroid swelling. The present case emphasizes the potential risk of acute thyroid swelling associated with every FNA procedure.