AIM:To evaluate the effect of hammerhead ribozyme 213 (Rz 213) against hepatitis C virus (HCV) infection. METHODS:Rz213 cleaving 5'noncoding region (5'NCR) of HCV was beforehand transfected in a human hepatic carcinoma cell (HHCC) line and selected for G418 resistance. Cells stably expressing Rz213 were retransfected with pCMVNCRluc containing 5'NCR-luc fusion genes by lipofectAMINE;luciferase activity in lysate of transfactant was measured in scintillation counter. RESULTS:HHCC cells stably expressing Rz213 exhibited significant resistance to retransfection of targeting gene.