Purpose : To find the CT and US findings of multilocular cystic renal cell carcinoma. Material and Methods :We retrospectively analysed CT and US findings of five cases of the pathologically proven multilocular cysticrenal cell carcinoma. We analysed CT and US with view points of tumor margin, growth pattern, renal contourchange, echogenicity, attenuation on pre- and postcontrast scan, thickness and number of septum, and perirenalchange. Results : The CT findings of the multilocular cystic renal cell carcinoma were large well defined roundencapsulated multiple fluid filled cystic mass with exophytic growing pattern. The capsule and septum wererelatively well enhanced with contrast medium. The cystic space and septum were variable in size and shape. USrevealed large multiple fluid filled cystic mass separated by echogenic septum. Conclusion : The above CT and USfindings of multilocular cystic renal cell carcinoma may be helpful in the diagnosis.