OBJECTIVE: To investigate whether polymorphism of CYP19 gene is associated with the risk of advanced endometriosis in Korean women. METHODS: Blood samples were collected from 202 endometriosis patients and 221 controls. The patients with endometriosis of stages III and IV diagnosed by both pathologic and laparoscopic findings to according modified AFS classification. The women undergoing laparoscopic surgery or laparotomy for non-malignant lesions were included in the control group. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) of PCR products were done to determine all individuals' genotype. RESULTS: The heterozygous allele in CYP19 gene was the most common genotypes in both endometriosis and healthy control groups (52.0% vs. 46.1%). CYP19 gene polymorphisms did not show the significant differences between the control group and endometriosis group. CONCLUSION: The results suggested that the CYP19 genetic polymorphism was not associated with a risk of advanced endometriosis in Korean women.