Primary mucus-Producing adenocarcinoma of the renal pelcis has been one of the varest tumors of the genitourinary tract. The pathogehesis of the primary adenocarcinoma of the renal pelvis seems to be closely relasted to long standing chronic pyelonephritis usally associated with calculi. The tumor is well circums crived round cystic mass with thin peripheral rim and internal strand like calcifica-tion on CT and hypovcisular mass on angiography. We report a case of mucinous adenocarcinoma of the renal pelvis by pathology with a brief review of the literature.