Various epidemiological studies agree to a general prevalence rate of 3-10% in the reproductive age group. Studies have suggested that the ectopic endometrial tissue responds to endogenous and exogenous hormones very much like the eutopic endometrium. Hence, the endometrial fragments in the peritoneal cavity are responsive to ovarian hormone regulation. It is easy to see how endometriosis can be labeled as an endocrine disease in view of the role of endogenous hormones in its pathophysiology, development and treatment options. Endometriosis is a steroid dependent condition which histologically is similar to the endometrium. However quantitative differences exist between endometriosis and endometrium in response to hormonal environment, this may be due to the variations in expression of steroid receptors. Although finer details of pathogenesis and treatment remain to be studied and are continually being updated, the two essential components which are estrogen and endometrium have been proven beyond doubt to be the main components of endometriosis.