Abstract: Objective To identify functional SNPs in the COX-2 promoter and evaluate its effects on risk of endometriosis.Methods The genomic DNA of each subject was extracted by proteinase K digestion followed by saturated hydroxybenzene/ chloroform procedure.Genotypes of COX-2 -1195 promoter of 120 endometriosis cases and 240 controls were determined by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP).Results The frequencies of GG、AG and AA genotype of COX-2 -1195 promoter were 14.2%、50.0% and 35.8% in 120 patients with endometriosis，24.6%、53.3% and 22.1% in 240 controls respectively, and there was a significant difference between cases and controls. A greater risk of developing endometriosis is observed for A-1195 containing haplotype compared with other haplotypes. It was revealed a 1.63-fold (95%CI=0.87-3.03) and 2.82-fold (95%CI =1.44-5.52) excess risk of developing endometriosis in the individual for -1195A and -1195AA containing haplotype respectively. Conclusion The single nucleotide polymorphism of COX-2-1195G>C promoter may play an important role in genetic basic to endometriosis.