BACKGROUND & OBJECTIVE: Hepatocellular carcinoma (HCC) often results in portal vein tumor thrombus (PVTT), and the prognosis of the patients is extremely poor. It has been reported that some oversea scholars achieved fine therapeutic effects in treatment of this disease by 3-dimensional conformal radiation therapy (3DCRT) in fractionated conventional dose. The aim of this study was to evaluate the efficacy of 3-dimensional conformal hypofractionated single high-dose radiotherapy combined with transcatheter arterial chemoembolization (TACE) for portal vein tumor thrombus in patients with hepatocellular carcinoma. METHODS: From May 1998 to December 2000, 35 patients with unresectable HCC complicated with PVTT were treated with 3-dimensional conformal hypofractionated single high-dose radiotherapy and TACE. According to the volume of the tumors, radiotherapy was performed at an exposure of 4-8 Gy/time, 3 times/week, 48-60 Gy, 8-12 times, 3.0-3.5 weeks. The objective responses were analyzed and the survival rates were assessed from the date of the beginning of treatment using the Kaplan-Meier method. The Cox proportional hazards model was used to analyze the prognostic factors. RESULTS: The objective response was 71.4%. The overall survival rates were 59.3%, 31.6%, and 26.6% at 1, 2, 3 years, respectively, with a median survival time of 11 months. Cox proportional hazards model analysis showed that Child-Pugh class was the most important prognostic factors for the survival probability of the patients. Radiation-induced liver disease (RILD) and gastrointestinal bleeding were the most common treatment-related complications. CONCLUSIONS: 3-Dimensional conformal hypofractionated single high-dose radiotherapy combined with TACE is an effective and feasible approach to treat PVTT in unresectabe HCC patients. Child-Pugh class was identified as a predictor for PVTT in unresectabe HCC patients.