A review on a class of drugs for hepatitis C virus (HCV) that target the NS3/4 viral protease.Selected protease inhibitors (telaprevir, boceprevir, TMC-435, MK-7009, PHX-1766, R7128/ITMN-191, ITMN-191, VBY-376) in HCV clin. trials are presented.Triple therapy (investigational drug combined with PEGylated interferon plus ribavirin) is discussed in the treatment of most patients chronically infected with HCV genotype 1.