Health care workers (HCW) are a population at high risk of hepatitis B virus (HBV) infection, especially in endemic countries such as Lao PDR. Effective vaccines are available since over 10 years, but many HCWs are not aware of the risk of infection and are still not immunized against hepatitis B. This study aimed to assess immunization coverage against hepatitis B among the students of the University of Health Sciences (UHS) of Lao PDR in 2013 and to look for the causes of non-vaccination. A cross-sectional survey was conducted by self-administered questionnaire on a representative stratified sample of each academic year in each faculty. In total, 961 questionnaires were collected, Basic Sciences: 143, Medicine: 167, Pharmacy: 148, Dentistry: 139, Nursing Sciences: 159, Medical Technology: 99, and Postgraduate Studies: 106. Respondents were predominantly female (59.1%), mean age 25.1 +/- 7.0 years, single (76.3%), from the provinces (68.0%), of the Lao Loum ethnic group (84.4%). Among them, 21% were fully vaccinated against hepatitis B and 9.5% partially. Immunization coverage rates were significantly higher among women (p = 0.01), students aged over 25 years, married or belonging to the post-graduate faculty (p < 0.001). The most common reason (38.6%) given for non-vaccination was not knowing where to get vaccinated. Knowledge about hepatitis B, scored from 0 to 5, was poor (0-1) for 86.5% of the students, but 77.5% were aware of the hepatitis B vaccine. The knowledge scores were significantly higher for students aged over 25 years, married or post-graduated (p <0.001). Vaccination coverage against hepatitis B is dramatically low among students of health professions in Laos, largely because of their lack of knowledge and awareness. Upon admission to the University, all future HCWs should receive information about the occupational risks of blood-borne viruses transmission and be encouraged to get vaccinated against hepatitis B. (C) 2014 Elsevier Ltd. All rights reserved.