Since hepatitis B vaccine was first released in 1981, a public health goal has been to vaccinate adults at risk for infection because of risky sexual behaviors and needle-sharing practices. However, vaccination coverage for this group has remained low. During 2007, in the United States, among the estimated 43,000 persons newly infected with hepatitis B virus (HBV), the highest rate was reported among persons aged 25-44 years, and the majority of these infections were among at-risk adults. Surveillance data were similar in California. In 2006, when the Advisory Committee on Immunization Practices (ACIP) recommended that hepatitis B vaccination be offered to all adults as part of routine prevention services in settings where a high proportion of those served are at increased risk, CDC launched a national initiative encouraging states to use existing federal funds to purchase adult hepatitis B--containing (HepB) vaccine. In response, the California Department of Public Health (CDPH) established the Adult Hepatitis Vaccine Project (AHVP) to expand hepatitis B vaccination in sites serving at-risk adults. This report summarizes results for 2007-2008, which indicated that 28,824 doses of HepB vaccine were administered at 29 participating sites in the first 19 months of AHVP; 13 sites administered HepB vaccine for the first time. Federal provision of vaccine resulted in vaccination of many adults who otherwise might not have been vaccinated against HBV. Increased capacity to vaccinate all adults at risk is needed for the elimination of HBV transmission in the United States.