The relationship between the cyclooxygenase 2 (Cox-2) gene and pterygium formation is not well understood. In this study, the association and interaction between genotypic polymorphisms in Cox-2 gene and pterygium formation were investigated. 113 patients with pterygium and 400 healthy controls (without pterygium) enrolled from the Chang-Hwa hospital in central Taiwan were genotyped by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). Six polymorphic variants of Cox-2 were selected from the NCBI website and investigated, including G-1195A, G- 765C, T+8473C, intron 1, intron 5, and intron 6, and the association of specific genotypes with susceptibility to pterygium was analyzed. The data showed that, none of the Cox-2 G-1195A, G-765C, T+8473C, intron 1, intron 5, and intron 6 were found to have difference in the distribution between the pterygium and the control groups (P＞0.05). These findings suggest that, Cox-2 may have only post-transcriptional or post-translational regulatory effects on pterygium formation, not at the genetic level.