Silk suture reaction (i.e.,a benign granulomatous inflammatory foreign body reaction) is a rare complication of thyroid surgery. Here, two cases of post-thyroidectomy suture reaction are presented. Both of the patients were female, one is 48 and the other is 34 years old. The patients were presented with neck swelling and leakage of serous fluid from the Kocher's incision. Both patients had normal free T-4, free T-3, and TSH values. The 48-year-old female patient had a right subtotal and left near-total thyroidectomy 6 years ago and the other had bilateral total thyroidectomy 6 years ago. In the physical examination a mobile, painless, red, swelling was palpated in front of neck. In the ultrasound of both patients, a heterogeneous nodule with hypoechoic rim was seen, however, in scintigraphy no radiopharmaceutical involvement was observed in thyroid region. Due to suspicion of thyroid malignancy, a fine needle aspiration biopsy was performed and foreign body reaction was revealed cytologically. A suture reaction can vary from an erythematous swelling to chronic granulomatous reaction. The time interval between the operation and formation of suture reaction was 6 years in both of the cases thus these patients were considered as chronic patients. Foreign body reaction diagnosis was confirmed with fine needle aspiration biopsy. It is important to diagnose these chronic inflammation cases since these cases can mimic recurrence in thyroid malignancies. A post-thyroidectomy suture reaction is diagnosed cytologically with fine needle aspiration biopsy and by surgical removal of suture, this chronic inflammatory reaction can be cured.