Precise evaluation of the effect of treatment after ablation of liver tumors is essential. We encountered a case of hepatocellular carcinoma (HCC) in which tumoral necrosis was fairly well detected by intravenous contrast-enhanced ultrasonography (EU). An eighty-year-old woman with chronic hepatitis C underwent ultrasonographic examination (US), in which B mode US detected an HCC nodule 11 mm in diameter. This nodule was well enhanced by EU using the dynamic flow method and an ultrasound system (Toshiba PowerVision 8000) on both vascular and perfusion images. After percutaneous microwave coagulation therapy, the nodule was not enhanced by this method or enhanced CT. We think that EU should be the first choice of examination after nonsurgical treatment of liver tumors, because EU is more convenient than CT or MR and may have the same diagnostic ability to evaluate tumor viability as CT or MR.