The purpose of this study is to estimate the prevalence of the hepatitis B virus (HBV) infection and to examine factors related to HBV screening and vaccination among various Asian and Latino populations in Alameda County, CA. A cross-sectional study was conducted on Asian and Latino residents who registered with an HBV screening program from June 2009-February 2011. All participants completed a sociodemographic survey and were offered free HBV blood testing for the hepatitis B surface antigen (HBsAg) and antibody (HBsAb). The 3-shot vaccination series was provided for free to unprotected participants. Among the 792 registered participants, 84.4% (n = 669) received a blood test. Of the 669 tested participants, 7.9% (n = 53) tested HBV positive (HBsAg+, HBsAb -), 46.2% (n = 309) were protected (HBsAg -, HBsAb +), and 45.9% (n = 307) were susceptible to HBV infection (HBsAg -, HBsAb -). Among those unprotected, 60% completed the vaccine series. Multivariate analysis showed that being Vietnamese (OR = 5.53, 95% CI 1.54, 19.85), living in the US >10 years (OR = 2.12, 95% CI 1.13, 3.97), and having at least a college education (OR = 2.55, 95% CI 1.28, 5.07) were important predictors of vaccine completion. Given the various HBsAg + prevalence, screening, and vaccine completion rates among the different ethnic groups in this study, it is clear that different approaches in screening and vaccinating individual ethnic groups for hepatitis B are warranted.