PURPOSE: To evaluate the safety and the influence of embolization of severe arterioportal shunts, and the effect of the procedure on the survival rate of patients with hepatocellular carcinoma combined with portal vein tumor thrombosis. MATERIALS AND METHODS: This study involved a total of 54 patients with hepatocellular carcinoma in whom hepatic arteriography revealed severe arterioportal shunt. From among this total, 34 patients (embolization group) underwent chemoinfusion after shunt embolization, while 19 (control group) underwent chemoinfusion only. The embolic materials included PVA particles and/or Gelfoam pieces. The frequency of postembolization symptoms (Chi-squared test) and changes in laboratory values (paired t-test) were compared between the two groups, and shunt improvement was also evaluated. Patient survival was tested using the Kaplan-Meier method. RESULTS: Fever and RUQ pain were more frequent in the embolization group (p<0.001). The complications of embolization included severe postembolization syndrome (n=1), acute hepatic failure (n=2), hepatic infarction (n=1), and sepsis (n=1). There were no significant changes in laboratory values. Among the 28 patients (24 of embolization group and four of control group) who underwent follow-up angiography, arterioportal shunt became less severe or disappeared in ten of the embolization group. For the embolization and control groups, the mean survival interval was 29.5 +/-5.4 weeks and 10.3 +/-3.1 weeks (p=0.0002), respectively. The best results were seen in the PVA particle group (p=0.01). CONCLUSION: The embolization of severe arterioportal shunts is relatively safe and increases patient survival rate.