The ribosome inactivating proteins (RIPs) from plants possess RNA N-glycosidase activity that depurinates the major rRNA, thus damaging ribosome in an irreversible manner and arresting protein synthesis.  RIPs occur in fungi, bacteria and plants and are abundant in angiosperms, where they appear to have defensive role. RIPs are presently classified as rRNA N-glycosidase in the enzyme nomenclature (EC 3.2.2.22) and do exhibit other enzymatic activities such as ribonuclease and deoxy-ribonuclease activities ¹. RIPs have been shown to manifest anti-viral,anti-tumor, and anti-microbial activities. The RIPs have attracted a great deal of attention because of their potential use in medical research and development. Here, we describe purification and characterization of single chain Type-1 ribosome inactivating proteins (RIPs). We will present RIPs antiviral activity is broad since it impedes virus replication and could be used as an antiviral agent. ²