A case of solitary metastasis of renal cell carcinoma to the thyroid gland is reported. A 63-year-old-woman had been found to have an abnormal mass in the neck since April, 1986. She had a past history of right nephrectomy owing to right renal tumor 6 months earlier. Histological examination of the renal tumor revealed, common type, alveolar type, G1, INF alpha renal cell carcinoma. No metastasis was found on abdominal CT, chest tomography and bone scintigram at that time. Radical thyroidectomy was performed on June, 23, 1986. Histological examination by hematoxylin and eosin staining revealed metastasis of renal cell carcinoma, and immunohistochemical technique ruled out primary thyroid carcinoma. Postoperatively no other metastasis was found on head-chest-abdomen-CT, chest-tomography or bone scintigram. Therefore no particular adjuvant therapy was performed.