BACKGROUND/AIMS: Korean population has been suggested to be minimally exposed to hepatitis A virus (HAV) for recent 20 years. Therefore, hepatitis A epidemics may occur among medical students and medical personnels who care the asymptomatic patients with hepatitis A. We investigated the changes in anti-HAV IgG positive rate among the medical students for 10 years and the curren anti-HAV IgG positive rate among the medical personnels in Chinju. METHODS: Serum anti-HAV IgG was measured using the commercially available HAVAB radioimmunoassay kit. The sera had been collected from 780 sophomore medical students during 1988-1997 and from 95 pediatric medical personnels at the Gyeongsang National University Hospital in December, 1997. RESULTS: The anti-HAV IgG positive rate of the sophomore medical students was 87.5% in 1988, 86.7% in 1989 83.8% in 1990, 75% in 1991, 85% in 1992, 70% in 1993, 56.3% in 1994, 58.8% in 1995, 53.8% in 1996 and 38.8% in 1997. The anti-HAV IgG positive rate among the pediatric medical personnel (mean age +/-S.D.; 26.4 +/-3.1) was 65.3%. CONCLUSIONS: These suggest that the population susceptible to HAV exists among medical students and pediatric medical personnels. Therefore, we should se up the preventive modalities against hepatitis A virus infection among these high risk groups.