In the present study, cloning of hepatitis B core antigen (HBcAg) gene and expression of the gene in eukaryotic cells have been reported. For this purpose, initially, HBcAg gene which was previously cloned into pUC19 plasmid, was excised by EcoRI ve HindIII from this plasmid and inserted into an eukaryotic expression vector pcDNA3. Afterwards, the resulting recombinant plasmid (pcDNA-HBc) was transfected into Vero cells, and the stable transfected cells (Vero-HBc) were selected in geneticin containing culture medium. The presence of HBcAg gene in Vero-HBc cells were confirmed by polymerase chain reaction and, the expression of HBcAg gene by Vero-HBc cells were tested in Western Immunoblotting assay. As a result, a 21 kDa protein reacting with anti-HBc antibodies which Vero-HBc cells indeed expressed, were detected at the end of this assay.