BACKGROUND Multiple medications are more effective than single agents for postoperative pain management. We investigated the analgesic effects of an intravenous combination of acetaminophen and ibuprofen immediately after thyroidectomy. METHODS In this double-blind clinical trial, 62 patients who underwent thyroidectomies were randomized to either the treatment (1000 mg acetaminophen, 300 mg ibuprofen) or control (1000 mg acetaminophen) group. Postoperative pain intensity was assessed using the visual analog scale (VAS) 0, 15, and 30 min after recovery room admission. Opioid rescue consumption was also recorded. RESULTS The VAS scores were significantly lower in the treatment than in the control group 15 [3 (2-4.3) vs. 5 (3-6); p = 0.015] and 30 [3 (2-4.3) vs. 4 (3-5); p = 0.018] min after recovery room admission, as were the opioid rescue dose requirements (p = 0.033). CONCLUSIONS Combined intravenous acetaminophen and ibuprofen may be better than acetaminophen alone for immediately acute postoperative pain after thyroidectomy.