In this study; it is aimed to evaluate the effect of preoperative single dose dexamethasone on postoperative nausea, vomiting (PONV) and pain patients planned for thyroidectomy. Forty patients, ASA I-II, scheduled for thyroidectomy were included in this randomized, double-blinded and placebo controlled study. The patients were randomly divided into two groups. A blind investigator administered dexamethasone 8 mg iv (Group D, n=20) or 2 ml saline (Group S, n=20) to the patients. Anaesthesia induction was performed with propofol 2mg kg-1, 2 μg kg-1 fentanyl and rocuronium 0.6 mg kg-1. Sevoflurane IMAC was used in all patients for the maintenance of anaesthesia. Pain (VAS pain scale), PONV (0-3 scale), the time for first analgesic need, total analgesic need, reaction to dressing, infection of insicion and mobilization time were recorded at postoperative 0, 15, 30, and 45th min and two hours intervals in first day. The postoperative VAS scores, PONV value and total analgesic need of Group D were significantly lower than Group S (p<0.05). There was no difference between the reaction to dressing and mobilization time of the groups. In conclusion preoperative dexamethasone administration less postoperative pain and PONV in thyroidectomy.