Abstract Background Hepatitis A is the most common type of hepatitis reported in the United States. Prior to hepatitis A vaccine introduction in 1996, hepatitis A incidence followed a cyclic pattern with peak incidence occurring every 10–15 years. During 1980–1995, between 22,000 and 36,000 hepatitis A cases were reported annually. Since 1996, hepatitis A vaccination recommendations have included adults at risk for infection and children living in communities with the highest disease rates. This study provides the first national estimates of self-reported hepatitis A vaccination coverage among persons aged 18–49 years in the United States. Methods We analyzed the 2007 National Immunization Survey-Adult (NIS-Adult) data with restrictions to individuals aged 18–49 years. National estimates of hepatitis A vaccination coverage were calculated based on self-report and multivariable logistic regression analysis was used to identify factors independently associated with hepatitis A vaccination status. Results Among adults aged 18–49 years, 12.1% (95% confidence interval, CI = 9.9–14.8%) had received two or more doses of hepatitis A vaccine in 2007. Hepatitis A vaccination coverage was significantly higher among adults aged 18–29 years (15.6%) and adults aged 30–39 years (12.9%) compared with adults aged 40–49 years (8.3%). Coverage was significantly lower for Hispanics (7.1%) compared with non-Hispanic whites (12.5%). Characteristics independently associated with a higher likelihood of hepatitis A vaccination among persons aged 18–49 years included younger age groups, persons at or above poverty level, persons with public medical insurance, and persons who received influenza vaccination in the past season. Conclusions In 2007, self-reported hepatitis A vaccination coverage among adults aged 18–49 years was 12.1%. These data provide the first national hepatitis A vaccination coverage estimates among adults and are very important in planning and implementing strategies for increasing hepatitis A vaccination coverage among adults at risk for hepatitis A.