Endometriosis is a complex disease with different degrees of expression. Although using ultrasound (US) with the transvaginal and transabdominal approaches yields a lot of information, especially about adnexal endometriosis, magnetic resonance (MR) is the modality of choice to see its exact stage. Several signs are not absolutely pathognomic but have high sensitivity and specificity in identifying endometrial ovarian changes. T2 shading sign (dropping signal intensity on T2) was for 2 decades thought as the most important technique until complete and incomplete rim sign and T2 dark spot sign were also established to help in reaching diagnoses. As all these signs are based on the behavior of blood products, they can be found in hemorrhagic cysts as well. Active debate persists about surgery indications for patients who are in the program of in vitro fertilization (IVF) and the influence of endometriosis per se versus surgery on the ovarian reserve. Although some potential difficulties might be encountered during aspiration and other manipulations during IVF, the influence of hormones during pregnancy could have even a therapeutic effect in some cases.