Received March 17, 2009
Accepted June 10, 2009

Endometriosis is a benign gynecological disorder affecting women of reproductive age and can have a varied symptomatology including chronic pelvic pain, dysmenorrhea, and infertility. The association of endometriosis and infertility has been recognized for years, although definite evidence of causality still eludes us. It is clear that in the advanced stage of the disease with mechanical disruption of the pelvic anatomy, infertility is easly explained. Nevertheless, the link between early stage endometriosis and infertility remains a source of controversy. The mechanisms of infertility associated with endometriosis include abnormal folliculogenesis, elevated oxidative stress, altered immune function, and hormonal milieu in the follicular and peritoneal environments, and reduced endometrial receptivity. These factors lead to poor oocyte quality, impaired fertilization, and implantation. In this manuscript we review the medical literature concerning the pathophysiology of the endometriosis-related infertility.