Allosteric inhibition of the hepatitis C virus (HCV) NS5B RNA-dependent RNA polymerase enzyme has recently emerged as a viable strategy toward blocking replication of viral RNA in cell-based systems. We report here 2 series of indole-N-acetamides, bearing physicochemically diverse carboxylic acid replacements, which show potent affinity for the NS5B enzyme with reduced potential for formation of glucuronide conjugates. Preliminary optimization of these series furnished compounds that are potent in the blockade of subgenomic HCV RNA replication in HUH-7 cells.