Hepatitis B virus (HBV) infection is one of the most widespread viral infections of humans. An effective way to treat and prevent the disease is vaccination. Since production of conventional HBV vaccines is very expensive, use of transgenic plants as an alternative bioreactor has recently become of interest to many researchers. In this study, the HBsAg gene has been transferred to pepper plants (Nicotiana tabacum) through the leaf disk technique. The recombinant plant expression vector, pCAMBIA containing HBsAg was cloned into E. coli strain JM107 and was then introduced into Agrobacterium tumefaciens strain LBA4404. Young tobacco leaves were used as explants and co-cultivated with A. tumefaciens. The transformants were regenerated on selection medium containing 1mg.l^-1 BAP, 0/1mg.l^-1 NAA, 500 mg.l^-1 cephotaxim and 15 mg.l^-1 hygromycin. After the growth of plantlets (about 15 cm), genomic DNA was extracted from putatively regenerated plants by the CTAB method. The presence of HBsAg gene in transgenic plants was detected using PCR analysis. Finally expression of HBsAg gene was tested via RT-PCR analysis.