Aim: We examined whether intramuscular parecoxib administration has a preventive or therapeutic effect on vasospasm following experimental subarachnoid hemorrhage (SAH). Materials and Methods: Twenty New Zealand White Rabbits were assigned randomly to one of four groups. Animals in Group I were not subjected to SAH (control group). Animals in all other groups were subjected to SAH. Animals in Group II received no treatment after SAH induction (SAH group). Animals in Group III received intramuscular parecoxib (diluted with saline) injection at 6 and at 30 hours after SAH (treatment group). Animals in Group IV received only intramuscular saline injection at 6 and at 30 hours after SAH (vehicle group). Animals were euthanized by perfusion and fixation 48 hours after SAH induction. Basilar artery cross-sectional areas and wall thicknesses were measured. Statistical comparisons were performed using Kruskal-Wallis and Mann-Whitney U tests. Results: Basilar artery cross-sectional areas in the treatment group were significantly higher than in the SAH or vehicle group (p < .05). Basilar artery wall thickness in the treatment group was significantly smaller than in the SAH or vehicle group (p < .05). Conclusion: Our study revealed that intramuscular administration of parecoxib significantly attenuates vasospasm following experimental SAH.