Endometriosis is a progressive, estrogen-dependent, chronic inflammatory disease that affects approximately 6-10% of reproductive age women. Patients usually presents with symptoms, such as non-menstrual pelvic and abdominal pain, ovulatory pain, dyspareunia, dysmenorrhea, dyschezia, and/or changes to bowel or bladder function, which can be exacerbated during ovulation or menses. Endometriosis is a leading cause of unexplained infertility, accounting for up to 50-80% of cases. Currently, altered endometrial receptivity and progesterone resistance are some of the leading theories that could explain endometriosis-related implantation failure. In the endometrium, the B-cell chronic lymphocytic leukemia/lymphoma 6 (BCL-6) protein forms a complex that binds to and inactivates regulators of the progesterone pathway, leading to progesterone resistance, aberrant decidualization, implantation failure, and recurrent miscarriages in women diagnosed with endometriosis. Surgical diagnosis consisting of laparoscopy, with or without histologic confirmation, is still considered the gold standard for diagnosis of endometriosis. Development of noninvasive screening and diagnostic tests to accurately identify patients with endometriosis has become increasing popular. A screening test for endometriosis has been developed to detect endometrial BCL-6 overexpression in asymptomatic women with unexplained infertility or recurrent pregnancy loss. Positive endometrial BCL-6 testing has been associated with recurrent miscarriages and poor in vitro fertilization outcomes. When the underlying cause of endometrial inflammation secondary to endometriosis was treated, an improvement in subsequent live birth rates was seen. Endometrial BCL-6 testing has a high positive predictive value that could help physicians and patients undergoing infertility treatment to seek surgical evaluation for endometriosis, to improve their reproductive outcomes.