PURPOSE: To evaluate the charateristic CT and MR findings of primary ovarian fibromas. MATERIALS AND METHODS: We retrospectively reviewed 11 cases which had undergone precontrast and postcontrast scanning, and two in which cases T1-weighted (WI) and postcontrast T1WI and T2WI images had been done. All cases were pathologically confirmed after surgical resection. These masses were analysed on the basis of clinical symptom, age, size (longest diameter), laterality, margin, attenuation (unenhanced and enhanced), signal intensity (SI), calcification, and amount of the ascites. RESULTS: The patients' mean age was 46.6 (range, 22-81) years, and the longest diameter was 14.8 (range, 8-28)cm. All tumors were unilateral, and eight were located in the left ovary and five in the right ovary. In all cases, the tumor margin was well-defined; seven were lobulated, four were oval, one was round, and one was nodularly marginated. On CT scan, the masses showed mildl to moderate heterogenous enhancement with irregular lower density portions. The amount of the ascites was marked in three cases (23%) mild in two (15%), and minimal in three cases. Calcifications were seen in 3 of 11 CT cases (27%), and in one, this was extensive. On MR scans, signal intensity (SI) of the masses on T1WI was isoSI, relativetive to the uterine myometrium, and heterogeneously enhanced after infusion of contrast media. On T2WI, SI was slightly lower that of the uterine myometrium with internal high SI portions. CONCLUSION: The characteristic finding of ovarian fibroma is a unilateral, well-defined, oval or lobulated, solid mass with or without ascites and calcification. On CT scan, tumor has mild to moderate heterogeneous enhancement. On MR scan, SI of mass is isoSI on T1WI with heterogeneous enhancement, and low SI on T2WI due to fibrous component.