Since solitary metastatic renal tumors are not commonly diagnosed before death, the conclusive treatment of the metastatic renal tumor has not been established. We report three cases of metastatic renal tumors and discuss the indication of surgical therapy for metastatic renal tumors. The first case was in a 64-year-old male who underwent esophagectomy for squamous cell carcinoma. Seven months after the operation, a right renal tumor was found. The second case was in a 63-year-old male who underwent right upper pneumonectomy for adenocarcinoma with a right renal tumor, which seemed to be a solitary metastasis. The third case was in a 69-year-old male who underwent right pneumonectomy for adenocarcinoma. One month after the initial operation, a left renal cystic tumor was found. Since, in all cases, the tumors seemed to be solitary metastatic renal tumors without any other metastatic lesions, nephrectomy was performed. Unfortunately, however, the nephrectomy did not improve prognosis and all three patients did within 10 months after the nephrectomy. Nephrectomy may not be recommended in cases of metastatic renal tumors even if no other metastatic lesions can be found by various image examinations.