Mesenchymal hamartoma and hepatoblastoma are common causes of hepatic masses in pediatric population; they have similar radiologic and pathologic features. Herein, we present a case of mesenchymal hamartoma that was preoperatively diagnosed as hepatoblastoma. The mass was completely resected instead of being treated with preoperative chemotherapy. Postoperative pathological evaluation revealed mesenchymal hamartoma with free margins; the patient incidentally received the standard treatment. If we would have measured serum AFP in our patient, we could make the correct diagnosis preoperatively, because AFP increases largely in hepatoblastoma. When suspicious exists, serum AFP is a good guide in differentiating hepatoblastoma from mesenchymal hamartoma.