Chronic hepatitis C virus (HCV) infection is a clinically important liver disease with limited therapeutic options in a significant proportion of patients. Therefore, novel efficient therapeutic agents are needed. Because the 5¢- and 3¢-untranslated regions (UTRs) of HCV are highly conserved and functionally important for HCV replication, they are attractive targets for RNA-cleaving ribozymes or small interfering RNAs (siRNAs).