The safety and immunogenicity of different doses (2, 5, 10, and 20 micrograms of a recombinant hepatitis B virus (rHBV) vaccine containing the S and PreS2 sequences and produced in mammalian cells were compared to those of a plasma-derived hepatitis B virus vaccine (Hevac B Pasteur) in 482 volunteers. Local and general side effects were mild and transient. No transaminase level elevation and autoantibody production were observed. The antibody to hepatitis B surface antigen (HBsAg) seroconversion rates did not differ in the groups receiving the rHBV vaccine and the subjects receiving the plasma-derived vaccine. Both vaccines elicited levels of antibodies to HBsAg in greater than 90% of the participants. Geometric mean titers of antibodies to HBsAg induced by the 10- and 20-micrograms doses of the rHBV vaccine did not differ from that induced by the plasma-derived vaccine and were higher than those induced by the 2- and 5-micrograms rHBV vaccine doses. The striking feature of the rHBV vaccine compared to the plasma-derived vaccine was an early and high production of antibodies to PreS2, which may constitute an advantage in prevention of hepatitis B virus infection.