Hepatitis B virus (HBV) can be detected in saliva of carriers and epidemiological studies suggest human bite as a possible route of transmission. We report a case of acute hepatitis B that developed after an individual with learning difficulty was bitten by a fellow resident in a sheltered accommodation. The attacker was found to be a chronic carrier of HBV and virus was present in his saliva. The HBV in both men had identical genotype and sequence. Future studies are warranted to investigate the role of saliva as a vehicle of HBV transmission in the community.