Endometriosis is a benign but progressive disease, which impairs fertility and causes period pain. The incidence in reproductive age group is 10%. However, about 40–50% of infertile women are found to have endometriosis almost in any infertility clinic. It is generally believed that endometriosis does not cause infertility per se except when associated with tubal disease (2%). Nevertheless, distortion of pelvic anatomy, immunological disturbances and compromised egg quality are the key factors for impaired fertility. Endometriosis fertility index (EFI) is a good scoring system to predict the pregnancy outcome after normal conception (non-ART) following surgery. Functional status of tubes, fimbriae and ovaries are assessed. This chapter covers the minimal and mild endometriosis (stage I and II), endometrioma, excision versus ablation for ovarian endometrioma, effect of surgery for endometrioma on ovarian reserve, deep endometriosis, surgery before in vitro fertilization, surgery after failed in vitro fertilization, and surgery or in vitro fertilization after recurrent disease.