Quantitation of hepatitis B surface antigen (HBsAg) in hepatitis B-associated hepatocellular carcinoma (HBV-HCC) remains to be clearly defined. This study aims to determine the association of HBsAg quantity with intrahepatic HBV viral load and activity in both tumor and non-neoplastic liver of HBV-HCC patients. Data were obtained from 89 prospectively enrolled patients treated with primary liver resection for HBV-HCC at a single Western institution (2008–2013). Circulating HBsAg was quantitated using ELISA. HBV DNA, covalently closed circular (cccDNA) and precore-pregenomic RNA (preC-pgRNA) in both tumor and non-neoplastic liver were quantitated by real-time PCR from fresh liver resection specimens. Circulating HBsAg was detectable in all 89 patients. HBsAg negatively correlated with age, and positively correlated with pre-operative serum AFP and ALT levels. HBsAg correlated with HBV cccDNA copy number in tumor or non-neoplastic liver tissue. It also correlated with preC-pgRNA copy number in non-neoplastic liver tissue. HBsAg did not correlate with serum HBV DNA, total intrahepatic HBV DNA, viral replicative activity or transcriptional activity. In HBV-HCC patients, HBsAg levels correlated with cccDNA copy number in tumor or non-neoplastic liver tissue, suggesting that a greater pool of cccDNA is associated with a higher rate of HBsAg production. J. Med. Virol. 88:244–251, 2016. © 2015 Wiley Periodicals, Inc.