Infection with HBV is still one of the more important professional risk for medical staff. This is particularly true for dentists the more so when they are operating in areas at medium or high prevalence of HBsAg carriers. In such situation patients often ignore their carrier state, when they know it they are not always conscious of the importance of notifying the information to their dentist. The dentists, on the other hand, don't routinely collect a detailed anamnesis of their patients. For these reasons the opportunity of being vaccinated against hepatitis B with a DNA recombinant vaccine was offered to dentistry students of the University of Perugia. All participants were to be negative for hepatitis B markers of infection including HBsAg and anti HBs. All volunteers were to have normal aminotransferase levels, be in good physical condition and give their informed written consent. 48 students turned out to be eligible for vaccination, of them 35 were males, 13 females, mean age 23 years. About two months after the third dose, all the vaccinees had seroconverted and 70.4% of them showed antibody titres between 1,000 greater than or equal to 10,000 UI/l. That indicate that very likely the antibody persistence will be long lasting (at least 5 years). Side effects, light and of short duration, were rarely seen.