Abstract： Objective To investigate the pathogenesis of endometriosis by studying endometriosis coexisting with variable genital tract anomalies and analysis the association between obstructive or nonobstructive anomalies with endometriosis.Methods From January 2000 to April 2010,a total of 67 cases of endometriosis coexisting with genital tract anomalies undergoing treatment in Peking Union Medical College Hospital were studied retrospectively.Results According to subtypes of concurrent genital tract anomalies,67 cases were divided into 19 cases in obstructive group and 48 cases in non-obstructive group.(1) Age and symptoms:the mean age were (22 ± 8) years in obstructive group and (32 ± 7) years in non-obstructive group,which reached statistical difference (P ＜ 0.05).The major symptoms were dysmenorrheal or chronic pelvic pain (14/19) and amenorrhea (8/19) in obstructive group.However,in non-obstructive group,the major symptoms were dysmenorrheal or chronic pelvic pain (31％,15/48) and infertility (35％,17/48) and abortion (21％,10/48).(2) Degree and incidence of endometriosis:the moderate or severe endometriosis was 11/19 in obstructive group and 40％ (19/48) in non-obstructive group,which did not show statistical difference (P ＞ 0.05).The incidence of peritoneal endometriosis,ovarian endometriosis,adenomyosis did not show significant difference between two groups (all P ＞ 0.05).The rate of moderate or severe endometriosis coexisting with duplex uterus,uterus bicornis and uterus septus did not show significant difference in non-obstructive group (P ＞ 0.05).Conclusions The severity of endometriosis showed no association with obstructive anomalies.The results implied that there might be other factors involved in pathogenesis of endometriosis.