The diagnosis of ovarian tumor has been mainly dependent on manual pelvic examination and ultrasonography. Butin case of malignant ovarian tumor, CT has more advantages over ultrasonography in assessing anatomic details,relationships to bowel loops, precise extents of tumors and follow-up examinations after surgery. Authors analyzedCT features of 46 cases of patholgocially proven ovarian tumors for recent 4 years at keimyung University DongsanHospital. The results were as follows: 1. The msot common tumor was serous cystadenocarcinoma(9 cases:20%),followed by metastases(8 cases: 17%), mucinous cystadenocarcinoma(7 ases:15%), mucinous cystadenocarcinoma(5cases:11%), teratoma(5 cases:11%), lymphoma(3 cases: 7%) and dysgerminoma(2 cases:4%). 2. The ovarian tumors werevariable in size from 2.5cm to 33cm in diameter. Most of the solid tumors were smaller than 10cm in diameter andmost of the cystic tumors were larger than 10cm in diameter. Usually mucinous tumors were much larger than seroustumors. Mucinous cystadenomas were the largest tumors. 3. Unilateral tumors(left 19,right 13 cases) were morecommon than bilateral tumors(12 cases). Bilateral tumors were seen in serous and mucinous cystadenocarcinoma,metastases and lymphoma. 4. CT features of mucinous cystadenomas were smooth margins and thin wall of the tumormasses and multiloculated cysts with internal septa in all 7 cases. 5. In contrast, CT demonstration ofbilaterality, irregular margin, thick wall, enhancing solid lesions, septal irregularity, adhesion to adjacentstructures, peritoneal/omental implantation, ascites and hydronephrosis were signs suggesting malignancy. CTfeaturs of the serous cystadenocarcinoma were mostly solid to mixed nature(83%), irregular margin(75%), enhancingsolid lesion(67%), papillary growth (75%), internal septa(58%), multilocularity (58%) and calcification (25%) indescending order of frequency. 6. On CT, mucinous cystadenocarcinoma were irregular-marginated, thick-walled,cystic tumors with enhancing solid lesion, septal irregularity and signs of metastasis, although there were somecases having similar features of benign. 7. Among the extrapelvic CT findings of malignant epithelial ovariantumor, peritoneal/omental implants(11 cases:79%) and ascites(10 cases:71%) were the most common, and indistinctuterus(6 cases:43%), bowel adehsion(5 cases:36%) and pseudomyxoma peritonei (2 cases) were descending order offrequency. 8. CT features of teratoma were diagnostic having at least three more of different tissue densitiesamong fat, water, soft tissue and calcific densities. Also there were thick wall (4 cases) and fat-fluid level(1case). 9. In 8 cases of ovarian metastases, there were solid type tumor smaller than 10cm in 4 cases and hugecystic in 2 cases. The site of primary cancer were stomach in 4 cases, colon , cervix, endometrium and unknown ineach one case. 10. In 3 cases of malignant lymphoma, the CT featurs were solid in appearance, smaller than 10cmand accompanied by lymphadenopathy in all cases.