Three cases of metastatic renal tumor are reported. The first case was of a 61-year-old man, who had a Miles' operation for rectal adenocarcinoma 30 months before, and suffered from high fever and right flank pain. Right nephrectomy was carried out and the kidney was found to contain an adenocarcinoma identical to the one previously removed from the rectum. He died 1 year after nephrectomy. The second case was of a 35-year-old man, who had undergone left pneumonectomy for a squamous cell carcinoma of the bronchus. One month later, he was readmitted with cloudiness of consciousness and high fever. Investigations revealed right kidney, adrenal gland and brain malignancies, and which were ectomized totally. On pathological examination all ectomized tissues were metastatic squamous cell carcinoma. He died 1 month after the second operation. The third case was of a 48-year-old man, who had undergone left pneumonectomy for a squamous cell carcinoma of the bronchus. One year after pneumonectomy, abdominal CT showed a left renal tumor. Right nephrectomy was performed and pathological examination revealed a metastatic squamous cell carcinoma. He is now alive 4 months after nephrectomy without any sign of recurrence. A total of 136 cases of metastatic renal tumors including 38 cases from the Japanese literature, are reviewed.