[영문]Objectives. We sought to examine trends in hepatitis B virus (HBV) vaccination among high-risk adults and assess the potential effect vaccinated adolescents have on these trends as they age. Methods. We used data from the National Health Interview Survey 2000, 2002, and 2004 to examine trends in HBV vaccination among high-risk adults aged 18 to 49 years and in age subgroups (18?29, 30?39, and 40?49 years). We investigated temporal differences in vaccination rates for the 18- to 29-year-old cohort with model-based linear contrasts constructed from a logistic regression model with age and survey year as predictors. Results. There was a significant increasing trend in vaccination prevalence across the 3 survey years (32.6%, 35.3%, and 41.4%; trend test, P=.001). We found that respondents aged 18 to 29 years were more likely to be vaccinated in 2004 than in 2000, after adjusting for relevant confounders (odds ratio=1.73; 95% confidence interval=1.14, 2.6); there was no significant increase in vaccination for the other cohorts. Conclusions. A cohort effect, in which successfully vaccinated adolescents have reached young adulthood, contributes significantly to recent trends showing improved HBV vaccination among high-risk adults.