A sero prevalence survey of markers of hepatitis B virus (HBY) infection in children aged 0‐16 years was conducted in a mixed‐race township in western New South Wales. A total of 408 children were screened representing 95% of the total 0‐16‐year‐old population. Of the Aboriginal subjects, 69% had sero markers which indicated previous infection with HBYand 14% were hepatitis B surface antigen (HBsAg) sero positive. In the non‐Aboriginal subjects the prevalence of seromarkers was 10%with no subjects HBsAg positive. The township provided an ideal setting for studying possible crossinfectlon from children in a high risk (Aboriginal)population group to children in a low‐risk (non‐Aboriginal)group. The ratio of children in the high‐risk group for HBY infection to those in the low‐risk group was approximately 2.7:1. Although HBsAg was highly endemic in the Aboriginal population, the data Indicate that little crossinfection has occurred. We conclude that in this and similar mixed‐race communities action should be taken to accelerate vaccination programmes aimed at reducing HBY infection among neonates and children in the high‐risk groups. This will provide an immediate overall reductlon of potential risk to both high‐risk and low‐risk groups while the issue of universal vaccination is considered further.