Our report reviews the radiologic findings in 34 cases of duodenal malignant tumors with rare occurrence seen at Severance Hospipal between the year 1965 through 1979. Histologic diagnosis ispredominantly adenocarcinoma in cases of malignant tumors in the duodenum. Suprapapillary type showed polypoid mass with irregular mucosal ulcerin contrast to the annular constrictive lesions of infrapapillary. Irregular nodular filling defects or ulcer near the papillary area, associated with dialtation of gall bladder or common bile duct, were main characteristic radioligc features of periampullarycarcinoma. Leiomyosarcoma showed more prominant exoenteric growoth rather than intraluminal mass. But malignant lymphoma revealed relatively variable radiologic findings. The diffuse irregular mecosal thicknening in the dioenum can be considered as radioligic manfestations of rare diseases such as Extramedullary Plasmocytoma and Histiocytic Medullary Reticulosis.