Chronic hepatitis B virus (HBV) infection is the primary risk factor for the development of hepatocellular carcinoma worldwide. After decades of chronic hepatitis, about 30-40% of patients progress into liver cirrhosis, and of them, around 1-5% subsequently develop hepatocellular carcinoma (HCC) annually. Since the carcinogenic process involves the interplay between the hepatitis virus and the host hepatocytes, both genomes contribute to the final pathogenic outcome, either individually or synergistically. Studying the genetic factors predisposing hepatocarcinogenesis in both host and viral genomes will help illuminate the critical carcinogenic mechanisms, and create molecular targets for future therapy. In this article, we thus review the epidemiology of HBV-related HCC and viral factors involved in hepatocarcinogenesis.