Leiomyomas are the most common uterine neoplasms. Leiomyomas classified as intramural, submucosal, or subserosal are usually associated with various types of degeneration. The diagnosis and the treatment of leiomyomas vary among these subtypes of leiomyomas. Magnetic resonance imaging is the most accurate imaging technique for detection, localization, and characterization of myomas. The differential diagnosis at MR imaging includes adenomyosis and solid adnexal masses. Despite its relatively high cost, MR imaging is a very useful procedure which can assist preoperative planning.