There is functional endometrial tissue anywhere other than the uterine cavity and uterine mucosa with a penchant for infiltration and invasion. It is labeled as endometriosis. It is a chronic inflammatory condition. It can occur anywhere, but the most common site is the ovary. It is also labeled as endometrioma or Chocolate cyst. Other common sites for endometriosis are the pouch of Douglas (POD), posterior leaf of the broad ligament, uterosacral ligament, fallopian tube. Barin is the least common site for Endometriosis. Endometriosis is never seen in the spleen. This condition, which impacts 10–15 percent of women of childbearing age, is characterized by pelvic pain and infertility. Dysmenorrhoea, adnexal mass, and infertility are the classical triad of clinical features. This classical triad is mainly seen in the women of childbearing age but can also be seen in the women after menopause. Endometriosis is an estrogen-dependent condition that tends to go away on its own or after surgery. It tends to regress after menopause because it is an estrogen-dependent condition. Endometriosis is associated with cellular and humoral immunity also. Impaired immune function may contribute to the development of endometriosis. Despite this, up to 2.2 percent of women after menopause are affected. Endometriosis in postmenopausal women is seen mainly after elevated systemic estrogen concentrations or excess exogenous estrogen intake. In most women, symptomatic endometriosis after menopause begins more than ten years after menopause in the absence of elevated systemic estrogen concentrations or exogenous estrogen intake. This is necessary to understand the pathophysiology and management of endometriosis after menopause.