Endometriosis is the presence of endometriotic tissue outside of the uterus, composed of endometriotic glands and stroma. It affects between 10% to 12% of women in reproductive age. It presents with dysmenorrhea, dyspareunia, chronic pelvic pain, infertility, urinary or digestive symptoms. Diagnosis is based on clinical suspicion, clinical exam, pelvic ultrasound or pelvic magnetic resonance, and confirmed by laparoscopy with pathology studies. Its management is better understood nowadays. However, its association with neoplasia has been questioned for many years. It probably plays a role in the etiology of gynecological cancers, mainly ovarian neoplasia. In our review, we separately compared endometriosis and endometrioma to cancer, in terms of mutual causality, common risk factors, distinction based on histological findings, in addition to molecular and genetic pathways behind this association. This article reviews the English literature for studies on the association between endometriosis and gynecological cancers. Additional reports were collected by systematically reviewing all references from retrieved papers.