In this study, we describe the case of a 36-year-old woman who was diagnosed with hepatocellular carcinoma on a background of Fontan procedure for tricuspid atresia. She had worsening heart failure in the months before presentation, and early investigations noted derangement in liver enzymes and hepatomegaly. Liver biopsy confirmed a hepatocellular carcinoma. Hepatocellular carcinoma is a rare but recognised consequence of cardiac cirrhosis in Fontan patients.