Hammerhead ribozymes that target components critical to HSV replication (ICP4, UL20, UL30, and UL54) were synthesized and shown to efficiently cleave target RNA encoding a portion of these components in in vitro assays. Several cloned cell lines stably expressing these ribozymes were established. HSV-mediated plaque formation was dramatically reduced in cells stably transfected with an anti-HSV ribozyme compared to non-transfected cells.