We report a case of hepatocellular carcinoma located just below the right hemidiaphragm that was diagnosed as having hepatitis C virus-related cirrhosis 12 years ago. Although the lesion was not clear on conventional sonography, it was clearly defined on CO2-enhanced sonography, allowing safe and accurate radiofrequency ablation. By combining radiofrequency ablation with transcatheter arterial chemoembolization, extensive cauterization and complete tumor necrosis were obtained with only 1 session of treatment. The patient had no serious adverse effects and has shown no recurrence during 35 months of follow-up. VVC 2006 Wiley Periodicals, Inc. J Clin Ultrasound 35:78–81, 2007; Published online in Wiley InterScience (www.interscience.wiley.com).