Feline herpesvirus 1 (FHV-1) is a DNA virus that produces mainly upper respiratory tract disease in cats. Despite available vaccines and the labile nature of the virus, FHV-1 is wide-spread in the feline population. Approximately 80% of FHV-1 infected cats develop a latent infection and serve as reservoirs for the virus. Currently available antiviral treatments for herpesvirus infections have limited efficacy, and there is no effective therapy that specifically targets FHV-1. RNA interference therapy would specifically target FHV-1. RNA interference is a RNA-guided gene regulatory mechanism that is found in a variety of eukaryotic organisms, including yeast, plants, and mammals. One of its biological functions is anti-viral immunity in plants. This defense mechanism is triggered by double stranded RNA, and small interfering RNAs can be chemically produced and delivered to cells to silence specific genes of interest. RNA silencing has recently been used for prevention of various mammalian viral infections both in vitro and in vivo. The purpose of this study is to determine the feasibility of using RNA interference to prevent or treat FHV-1 infections in vitro and to lay the ground work for a new therapeutic approach for the treatment of FHV-1 infected cats.