Huanta is an Andean valley of Peru, located at 2400 meters above sea level with a population of 45,000 inhabitants. Viral hepatitis is widely known in the area due to its severe clinical symptoms and high morbidity and mortality. METHODS A study on the prevalence of hepatitis A, B and D markers among 143 clinically healthy school students was carried out. The students were selected randomly from 4 schools in the city. The subjects provided epidemiological data regarding viral hepatitis and a venous blood sample to determine HBsAg, anti HBc antibody, anti-HBc IgM, anti HAV and anti HDV by the ELISA technique (Abbott Lab.). RESULTS A total of 93 males and 50 females participated in the study. The mean age was 13.2 years (7-20 y.). Anti HAV was detected in 140 of them (98%). Prior infection by HBV was detected in 117 (82%) and an active infection in 4 of them (2.7%). The rate of HBsAg carriers was 16.0% (23). HDV infection was found in 21 of 117 (17.9%) individuals infected by the HBV. HBV infection and the previous use of injections represented a significant association (OR:3.7 IC 1.3-11, p < 0.012). No differences in sex were noted. CONCLUSIONS A high prevalence of HAV, HBV, and HDV was found among school students in Huanta and this was the first report of hepatitis delta in the area. The association of HBV infection and the use of injections was meaningful. The high prevalence of HBV and HDV suggests the existence of a relationship to the morbidity and mortality by hepatitis in Huanta, thus the need for control programs by means of immunization against HBV.