Endometriosis (the presence of endometrial-like tissue in sites outside the uterus) is a common condition, affecting 6-10% of women of reproductive age. Endometriosis is a chronic inflammatory disease that is associated with pelvic pain, painful periods, pain with sexual intercourse, and subfertility. It has a significant impact on health-related quality of life, as recent studies reported that endometriosis had affected work in 51% of the women and affected relationships in 50% of the women at some time during their life with a negative impact on quality of life, and it has been estimated that the health burden and public health costs associated with endometriosis are high with over 9000€ per woman per year in the EU. Current treatment strategies for endometriosis are restricted to surgical excision of the lesions or suppression of ovarian function to mimic a premature menopause. In up to 75% of cases, symptoms recur after surgery, and long-term ovarian suppression is often ineffective, suppresses fertility and has unwelcome side effects. Therefore, there is an unmet clinical need for new treatments for endometriosis. Identification of relevant molecular mechanisms which are functionally linked to the patient symptoms is therefore a major priority. The MOMENDO consortium was comprised of an internationally competitive and recognized interdisciplinary team dedicated to identifying novel pathogenetic mechanisms of endometriosis by utlilizing innovative techniques and etiological concepts, and by incorporating state-of-the-art topics in biomedical research. To reach this goal, we focussed on aspects of the disease which are of particular relevance to patient symptoms which have a major negative impact on quality of life, namely (i) molecular mechanisms of endometriosis-associated pain, (ii) new mechanisms linked to chronic inflammation in endometriosis, and (iii) novel, state-of-the-art etiological concepts (iron overload, microRNA involvement, endometrial stem cells). The knowledge generated by these studies was ultilized and combined with novel therapeutic concepts, including (iv) novel endocrine approaches, (v) a targeting of metabolic mechanisms in the inflammatory microenvironment, (vi) the use of herbal medicines with antioxidant activity and (vii) the induced differentiation of endometriotic and cancer stem cells as a tool of overcoming unlimited growth of endometriotic lesions and (viii) the use of iron-chelating reagents as an antiinflammatory measure in peritoneal endometriosis. Overall, MOMENDO made a major contribution to the molecular understanding of disease mechanisms which will help to develop new therapies for the disease.