In 1989, the prevalence of hepatitis B virus (HBV) markers was studied using Elisa method in a sample of 1357 healthy high school 14-19 year old teenagers in Sardinia. The overall prevalence of any HBV marker was 4.7%, increasing from 3.6% among 14-16 year old teenagers to 5.7% in 17-19 year olds. The overall prevalence of hepatitis B surface antigen (HBsAg) was 1.1%, similar in both age groups. A slight male preponderance was observed (5% versus 4.4% for any HBV marker and 1.7% versus 0.6% for HBsAg, respectively). The prevalence of any HBV marker was not associated with the family size (O.R. 1.5; CI 95% = 0.6-4.5), but it was inversely related to the number of years of education received by the father. Teenagers whose fathers had received less than six years of schooling had a 2.3 fold risk (CI 95% = 1.1-5.2) of previous exposure to HBV infection. Comparing these findings with recent results in children and adults in the same area, a cohort effect is likely evident.