Imaging of the pelvis via computed tomography (CT), ultrasound, or magnetic resonance (MR) provides excellent anatomical detail and superb resolution. Despite this, radiologists often have difficulty reaching a specific diagnosis in evaluating adnexal masses. A wide spectrum of benign extraovarian pathology may closely resemble ovarian cancer. Fallopian tube disease such as hydrosalpinx, tuboovarian abscess, and chronic ectopic pregnancy may mimic cystic or solid ovarian neoplasm. Pedunculated uterine leiomyomas may imitate ovarian lesions. Gastrointestinal causes of adnexal masses include mucocele, abscess, and hematoma. These entities may appear similar to ovarian lesions, thus requiring close attention to specific anatomical detail in order to help differentiate them. Similarly, peritoneal disease including tuberculous peritonitis and peritoneal pseudocyst may simulate ovarian tumor. While ultrasound represents the initial imaging modality in the evaluation of most pelvic disease, MR's multiplanar capability and improved tissue characterization make it a valuable modality in many circumstances.