Prevalence of three hepatitis B markers was measured by immunoassay techniques in small rural community of the State of S. Paulo, Brazil. Total prevalence was 7.74%, corresponding to values of 0.10%, 1.69% and 7.74% for HBsAg, anti-HBs and anti-HBc, respectively. The importance of anti-HBc determination in such studies is stressed. Comparisons between the low viral circulation observed in this area and high prevalences described in other rural communities may contribute to the raising of new hypothesis concerning alternative transmission mechanisms of hepatitis B.