The E2 glycoprotein is one of the structural components of the hepatitis C virus (HCV) virion. It elicits production of neutralising antibodies against the virus, and is involved in viral morphogenesis. The protein is considered as a major candidate for anti-HCV vaccine. Despite this, little is known about this protein. Previous studies have focused on the and functional analysis of the glycosylated forms. This report describes expression of the E2 (recE2) in different forms and in different expression systems in Escherichia coli cells and in mammalian cells in order to obtain enough protein efficiently in vitro, in addition we also analysed the usage of rare codons in the genes of E2 and CORE. All results have shown that great efforts should be made to improve the expression efficiency of E2 in bacteria or mammalian cells. The E2 glycoprotein is one of the structural components of the hepatitis C virus (HCV) virion. It elicits production of neutralizing antibodies against the virus, and is involved in viral morphogenesis. The protein is considered as a major candidate for anti-HCV vaccine. Despite this, little is known about this protein. Previous report have focused on the and functional analysis of the glycosylated forms. This report describes expression of the E2 (recE2) in different forms and in different expression systems in Escherichia coli cells and in mammalian cells in order to obtain enough protein efficiently in vitro, in addition we also analyzed the usage of rare codons in the genes of E2 and CORE. All results have shown that great efforts should be made to improve the expression efficiency of E2 in bacteria or mammalian cells .