Seventeen patients with suspected ovarian masses were evaluated by magnetic resonance imaging (MRI). MRI findings were confirmed by surgery (13 patients) or sonography and clinical follow-up (four). The study evaluated MRI characteristics of ovarian lesions using recently developed multislice and multiecho pulse techniques for a 0.15-T system. T1 and T2 relaxation times were calculated in 12 patients and although a range of values was obtained in several disease categories, diagnostic accuracy was frequently improved. MRI appearances tended to vary considerably with different pulse sequences and were particularly complex in patients with endometriosis and cystic ovarian tumors. Shortest calculated T1 and T2 values were found in hemorrhagic cysts in patients with endometriosis. Benign tumors with thick fibrous pseudocapsules had longer T1 values. Inflammatory masses and malignant ovarian tumors had significantly longer T1 and T2 values and relaxation times in a patient with mucinous cystadenoma varied within the complex mass.