BACKGROUND: As sanitary and economic conditions improve, the prevalence of antibodies to hepatitis A is now significantly lower. AIM: To evaluate the prevalence of hepatitis A virus antibodies in healthy Chilean adults. MATERIAL AND METHODS: Antibodies to hepatitis A virus were measured, using a commercial ELISA assay, in 215 voluntary blood donors (163 male, aged 19 to 30 years old) and 295 medical students and health personnel (156 male, aged 19 to 39 years old), residing in Valdivia, Chile. RESULTS: Antibodies against hepatitis A virus were found in 68.2% of the total sample (351/510). Ninety percent of flood donors and 54% of health personnel and students were positive (p < 0.01). Age specific prevalence in blood donors 19 to 22, 23 to 29 and 27 to 30 years old was 81.0%, 95.2% and 95.6% respectively. Among the same age groups in medical students, the prevalence was 47.9%, 53.2% and 61.9% respectively (p < 0.01). CONCLUSIONS: This study indicates a reduction in the prevalence of hepatitis A virus antibodies among adults in Valdivia (Chile). Differences detected between individuals are probably related to different socioeconomic levels. Medical students have an increased risk for hepatitis A infections than the general population.