Recurrent hepatocellular carcinoma (HCC) deserves multidisciplinary treatment in addition to surgical resection. Radiofrequency ablation (RFA) is an evolving, localized, thermal ablative treatment for unresectable hepatocellular carcinoma (HCC). Though the preliminary results of RFA in clinical studies are encouraging, its serious complications should not be underestimated. Portal vein thrombosis as a result of direct blood vessel injury by RFA is rarely reported and is potentially fatal in patients with limited liver reserve due to underlying liver cirrhosis. We present a case of portal vein thrombosis as a complication of RFA treatment for recurrent HCC and illustrate its underlying possible mechanism.