Universal Hepatitis B vaccination of adolescents has been recommended by the American College of Physicians. Logically, efforts to mass immunize adolescents have been implemented in the school systems. A shorter dosing schedule of the hepatitis B vaccine has been initiated in order to accommodate the academic year, although the efficacy is undocumented.Objectives: 1) To verify the immunity induced by a 0,2,4 month dosing schedule of the hepatitis B vaccine for adolescents and 2) to identify rates of hepatitis B infection in an adolescent population considered eligible for hepatitis B vaccination. Method: Adolescents from two general teen clinics in urban settings were randomly recruited to participate in receiving the hepatitis B vaccine series on a 0,2,4 month dosing schedule. Serologies for hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (HBcAb), and hepatitis B surface antigen antibody (HBsAb) were obtained at time 0 and at least 4 weeks after the third vaccination. Participants completed a one page risk behavior and demographic questionnaire.Results: 160 adolescents enrolled in the study. Of this group no known prior exposure or infection with hepatitis B was reported. Two subjects showed evidence of chronic hepatitis B infection, (HBcAb positive (+), IgM HBcAb negative (-) HBsAg +, HBsAb -) and one subject had evidence of past hepatitis B infection, (HBcAb +, HBsAb +, and HBsAg -). All three subjects were immigrants from the East Asia. Two had reported having sexual intercourse. Currently, 35 subjects have completed the study. 100% of the susceptible participants developed protective levels of antibodies against hepatitis B surface antigen with a geometric mean antibody titer of 1235 mIU. One subject with chronic hepatitis B showed no response to the hepatitis B vaccine. Conclusion: Our preliminary data shows that the 0,2,4 month vaccination schedule of hepatitis B is adequate to produce an appropriate immune response for hepatitis B in an adolescent population. However, the identification of chronic hepatitis B in this population raises the concern of inadequate detection of'at risk' groups. More evaluation of hepatitis B screening in adolescents may be necessary.