Endometriosis is a chronic, progressive, relapsing estrogen-dependent disorder characterized by the growth of tissue structure and function similar to the endometrium outside the normal mucosa of the uterine cavity localization. Endometriosis is found in 10–15% of women in reproductive age and it is one of the main causes of pelvic pain syndrome and infertility. Mechanisms of the development of endometriosis and related pathological pain impulses are still poorly understood and therapeutic approaches do not always have a sufficient effect; in this connection, the study of the pathogenesis of endometriosis and endometriosis-associated pain currently is perspective. Identification of significant factors of angiogenesis, lymphangiogenesis, and neurogenesis in the external genital endometriosis will promote the development of non-invasive early diagnosis and pathogenetic therapy.