The prevalence of chronic hepatitis B (HBV) among college-age US-born Asian and Pacific Islanders (A/PI) is not well known. Objectives: To compare the prevalence of hepatitis B surface antigen (HBsAg) seropositivity in US-born to A/PI-born students at a public university. Participants: Undergraduate who self-identified themselves as A/PI. Results: Of 145 US-born A/PI, 1.4% (confidence interval [CI] = 0.0%, 3.3%) tested positive for HBsAg compared to 3.3% (CI = 0.5%, 6.1%) of the 152 A/PI-born students. Approximately 1/3 of all students were unaware of their HBV vaccination status. Conclusions: HBsAg prevalence among A/PI undergraduates, including US-born, is considerably higher (3 to 11 times) than the mainstream US population (0.3% to 0.5%) and supports the Centers for Disease Control and Prevention (CDC) recommendations for testing all persons of A/PI ancestry, including US-born persons whose parents were born in regions with HBsAg prevalence of >/=8%. Awareness of HBV vaccination status was relatively low and vaccination did not assure that individuals were HBsAg negative.