Cystic disease in the female pelvis is common. The majority of cystic pelvic masses originate in the ovary, and they can range from simple, functional cysts to malignant ovarian tumors. Mimics of ovarian cystic masses include peritoneal inclusion cyst, paraovarian cyst, mucocele of the appendix, obstructed fallopian tube (eg, hydrosalpinx, pyosalpinx, and hematosalpinx), uterine leiomyoma, adenomyosis, spinal meningeal cyst, unicornuate uterus, lymphocele, cystic degeneration of lymph nodes, lymphangioleiomyomatosis, hematoma, and abscess. A cystic pelvic mass is nonovarian if it is separate from the normal ovaries. However, the different types of cystic pelvic masses may have similar imaging appearances, and radiologic evaluation may be of limited diagnostic use. It is important to understand the relationship of a mass with its anatomic location, identify normal ovaries at imaging, and relate imaging findings to the patient's clinical history to avoid misdiagnosis.