Abstract: 1183 children aged 1-9 years immunized with hepatitis B vaccine 9 years later were randomly sampled to evaluate the efficacy of a low dose immunization started in 1987 in a Zhuang Minority Area.The crude anti-HBs positive rate was 43.8%,and the age-specific rates were ranged from 87.9% (lst year )to 37.1% (9th year).The crude HBsAg positive rate was 1.6% and the efficacy of vaccination against B was 86.6%.The results showed that there was no evidence of necessity for revaccination against hepatitis B at present,and the high-dose immunization straregy should be recommended for further declining HBsAg posi-tive rate in the area.