Background: The character of a pelvic mass is not always clear on gynecologic and sonographic examination. Magnetic resonance imaging provides the chance to differentiate adnexal tumors from other masses. Materials/Method: Twenty-six women, aged 20-83 years, with suspicion of ovarian tumor, were examined with a 0.5 T unit in 3 cases and a 1.5 T unit in 23. Results: MRI allowed accurate diagnosis in 23 women (88.5%). Uterine myoma was shown in 8 cases, enlarged uterine cervix with large Nabothian cysts in 5, pyosalpinx in 2, nerve root cysts in 3, perirectal abscess in 1, colorectal tumor in 1, and ectopic pelvic kidney in 3. In 2 women, normal ovaries were not identified with the 0.5 T unit and in 2 with the 1.5 T unit. Conclusions: Magnetic resonance imaging, as a method with the highest resolution and tissue specificity, should be performed in every case of sonografically unclear pelvic mass.