Severe pain after third molar surgery is often encountered and more effective treatment regimes are warranted. The objective of this study was to evaluate if the combination of paracetamol and rofecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, improves analgesic effects following third molar surgery compared with rofecoxib alone. Paracetamol alone was also evaluated. Altogether 120 patients with moderate to severe pain after third molar surgery were given a single postoperative dose of one of the following treatments: rofecoxib + paracetamol; rofecoxib alone; paracetamol alone; or placebo. Patients assessed level of pain and pain relief every 30 min for 8 h after surgery, and made a global evaluation of the medication 4 and 8 h after surgery. Paracetamol and rofecoxib combined improved the analgesic effect compared with rofecoxib alone for the first 1.5 h. Rofecoxib alone and the combination of paracetamol and rofecoxib had a significantly better analgesic effect than paracetamol alone from 3 h onwards. The early onset of pain relief for the combination of paracetamol and rofecoxib, compared with rofecoxib alone, could be of great importance when treating acute pain after third molar surgery. After data collection for this study, rofecoxib was withdrawn from the market as a result of reported fatal cardiovascular events. Whether this is relevant for short-term use is unknown, but it has to be considered before rofecoxib may be used for pain relief following third molar surgery.