Background: Arthroscopic shoulder surgery under general anaesthesia is often associated with severe post-operative pain which may delay discharge and the start of rehabilitation. Etoricoxib is a new cyclo-oxygenase-2 inhibitor with a long duration of action and a lack of a deteriorating effect on platelet function. Therefore, the effect of pre-operative etoricoxib combined with local anaesthesia on post-operative pain and the discharge profile was studied in day-surgery patients undergoing arthroscopic shoulder surgery under general anaesthesia. Methods: Thirty ASA I–II adult patients scheduled for arthroscopic shoulder surgery were enrolled in this randomized prospective study. Half of the patients received etoricoxib 120 mg orally (group E) and the other half received placebo tablet orally (group C) 1 h before surgery. All patients received 20 ml of bupivacaine 2.5 mg/ml solution with epinephrine at the start of surgery and 20 ml of bupivacaine 5.0 mg/ml solution with epinephrine at the end of surgery into the subacromial space. All patients received general anaesthesia with spontaneous breathing via a laryngeal mask. In the post-anaesthesia care unit, pain was assessed on a scale from 0 to 10 (visual analogue scale, VAS) and intravenous fentanyl 25 g was administered as scheduled (VAS ≥ 3). In the day-surgery unit and at home, the analgesic was a tablet containing paracetamol 500 mg + codeine 30 mg (VAS ≥ 3), as needed. Results: Patients in group E reported lower post-operative pain scores at 30, 60, 120 (P < 0.01) and 180 min (P < 0.05) after surgery, and longer time to first analgesic use (P < 0.05). Patients in group E required less fentanyl (P < 0.05) and were discharged more quickly (P < 0.05) than patients in group C. Patients in group E had a lower cumulative consumption of paracetamol + codeine tablets (P < 0.05) and lower pain scores (P < 0.05) during 7 days at home than patients in group C. Adverse events were rare in both groups. Conclusion: In patients having arthroscopic shoulder surgery under general anaesthesia combined with intra-operative subacromial regional analgesia, etoricoxib 120 mg reduced immediate and late post-operative pain, and facilitated early post-operative discharge.