Primary mucus-producing adenocarcinoma of the renal pelvis has been one of the rarest tumors of thegenitourinary tract. The pathogenesis of the primary adenocarcinoma of the renal pelvis seems to be closelyrelated to long standing chronic pyelonephritis usally associated with calculi. The tumor is well circums cribedround cystic mass with thin peripheral rim and internal strand like calcification on CT and hypovcisular mass onangiography. We report a case of mucinous adenocarcinoma of the renal pelvis proven by pathology with a brief review of the literature.