Endometriosis is a disease condition where endometrial glands and tissues are present outside its uterine location mainly in pelvic peritoneum and on fallopian tubes and ovaries. It affects about 5-10% of women of reproductive phase and 20-50% of women who are suffering already with infertility. In the present article our aim is to review prevalence, causes and clinical characteristics for endometriosis. Overall updated literature survey showed that many factors such as hormonal, environmental, genetic and defective immune system are involved in the pathogenesis of endometriosis. These factors directly or indirectly alter the estrogen level which is responsible for varied and disabling symptoms with adverse effects on reproductive potential of women.