We report a case of splenic hamartoma, which is a rare entity, with renal cell carcinoma. A 45-year-old woman was incidentally found to have a splenic tumor and a left renal tumor at a medical checkup on suspicion of gastric submucosal tumor. Laboratory data on admission were normal. Abdominal ultrasonography and computed tomography (CT) showed a 7×5cm hypoechoic and low density solid mass in the spleen and a 3cm mass in the left kidney. On contrast CT scan, the splenic tumor was not enhanced. Splenic angiograms showed a hypervascular tumor. Laparotomy was performed on the diagnosis of left renal cell carcinoma and a suspicion of splenic metastasis. During surgery, the spleen was covered with normal capsule and swelled to the size of goose's egg; and the lesion which looked like gastric submucosal tumor was found to be caused by oppression due to a hepatic cyst in the lateral segment of the left hepatic lobe. A splenectomy and a left nephrectomy were performed. The cut surface of the resected spleen showed uncapsulated red tumor. The histological findings of the splenic tumor revealed a hamartoma consisting of red pulp components and the findings of renal tumor revealed renal cell carcinoma.