We report a rare case of secondary involvement of the gallbladder by metastatic renal cell carcinoma originating from ectopic kidney. The first diagnosis of the patient is a gallbladder carcinoma due to a polypoid mass within the gallbladder. The preoperative examinations revealed that there was also a synchronous renal cell carcinoma. The histopathologic examination of the polypoid mass and kidney after operation revealed the resected polypoid mass to be metastasis of renal cell carcinoma.