BACKGROUND Pain after craniotomy is often under-treated. Opiates carry distinct disadvantages. Non-steroidal anti-inflammatory drugs have an anti-platelet action and carry a bleeding risk. Cyclo-oxygenase 2 inhibitors such as parecoxib are not associated with a bleeding risk and would be welcome analgesics if shown to be effective. METHODS In a prospective double-blind, randomized, placebo-controlled study, we investigated the analgesic effect of a single dose of parecoxib 40 mg given at dural closure in 82 patients undergoing elective craniotomies. Remifentanil was used intraoperatively, and i.v. morphine was titrated to the requirement in the post-anaesthetic unit. On the ward, i.m. morphine 5 mg as required and regular acetaminophen was prescribed. Morphine use and visual analogue pain scores were recorded at 1, 6, 12, and 24 h after surgery. RESULTS Parecoxib reduced pain scores at 6 h and morphine use at 6 and 12 h after operation. However, overall, it had only minimal impact on postoperative analgesia. We found a wide variability in analgesic requirements where 11% of patients required no opioids and 16% required more than 15 mg i.v. morphine 1 h after the surgery. CONCLUSIONS We found only limited evidence to support parecoxib as an analgesic after craniotomy.