18 F-fluoro-2-deoxy-D-glucose ( 18 F-FDG) positron emission tomography (PET)/computed tomography (CT) has recently been shown to be able to predict a poor outcome after liver transplantation (LT) for patients with hepatocellular carcinoma (HCC). However, there are few reports on the usefulness of PET during follow-up after LT. In this study, we assessed the efficacy of 18 F-FDG PET/CT for the detection of HCC recurrence after LT. From February 2005 to December 2008, out of 93 adult LT cases (91 living donors and 2 deceased donors), 10 patients who showed HCC recurrence and received 18 F-FDG PET/ CT during follow-up were included. The accuracy of 18 F-FDG PET/CT was assessed with imaging and histological studies. The most common sites of recurrence were extrahepatic (60%). The most common extrahepatic sites were the lungs and bone (31.3% each). Among 4 patients with intrahepatic recurrence, 1 patient (25%) was positive according to 18 F-FDG PET/CT. The detection rate of 18 F-FDG PET/CT was 92.9% for extrahepatic metastases ! 1 cm and 0% for lesions < 1 cm. The detection rate of 18 F-FDG PET/CT was 100% in bone and the lymph nodes, 60% in the lungs, and 0% in the brain. 18 F-FDG PET/CT identified 2 lesions in bone that were not found in a bone scan. In conclusion, because of its limitations for small lesions, intrahepatic lesions, and brain lesions, 18 F-FDG PET/CT is not suitable as a screening tool after LT. However, 18 F-FDG PET/CT could provide additional information beyond that provided by conventional modalities, and it could contribute to the clinical management of HCC recurrence after LT, especially in patients with extrahepatic recurrence.