OBJECTIVE: To evaluate the relationship between advanced stage endometriosis and polymorphisms in alpha2-Heremans Schmidt glycoprotein (AHSG) gene in Korean women. METHODS: One-hundred thirty women with endometriosis stage III and IV, and 224 women without endometriosis were enrolled. In these patients, we determined AHSG gene polymorphisms by PCR and RFLP (restriction fragment length polymorphism) analysis. RESULTS: The genotype distribution of the AHSG gene polymorphism in the endometriosis group was not different from that of the control group (AHSG 1*1/AHSG 1*2/AHSG 2*2 frequencies were 56.2%/37.7%/6.2% and 55.8%/39.3%/4.9% for the endometriosis and control groups, respectively, p=.864). Also, the frequency of AHSG 2 haplotype was not different between endometriosis patients and controls (AHSG 1 haplotype /AHSG 2 haplotype rates were 75.0%/25.0% and 75.4%/24.6% for the endometriosis and control groups, respectively, p=0.894). CONCLUSION: AHSG gene polymorphism was not associated with the risk of advanced stage endometriosis in the Korean population.