Infection with hepatitis B virus (HBV) is common in Aboriginal Australians, but current seroprevalences in Northern Territory communities are unknown. We performed an audit of HBV serology on a convenience sample of 112 adults at an East Arnhem Land Health Service. Complete HBV serology was only available in 26 (23%) patients. Evidence of HBV exposure (core antibody-positive) was found in 43 of 68 (63%) patients tested, and current HBV infection (surface antigen-positive) was found in nine of 76 (12%). HBV is an incompletely defined, under-resourced and substantial public health problem in Aboriginal Australians.