We report a case of colon cancer with liver metastasis that had been treated previously by sigmoidectomy and partial hepatic segmentectomy. A 55-year-old woman presented with two asynchronous liver metastases, which were treated with percutaneous microwave coagulation therapy. However, evaluation by dynamic computed tomography one week later showed incomplete necrosis in at least one tumor. Surgical resection was subsequently performed and histopathological examination showed the presence of viable cancer cells in both tumors. We conclude that surgical resection is perhaps the best curative method of treatment of metastatic liver tumors of colorectal carcinomas and that dynamic computed tomography is not always accurate for evaluating the effect of microwave coagulation therapy.