Classical swine fever virus (CSFV) is an etiological agent of classical swine fever. The structure protein E-rns of CSFV assists in the initial attachment of the virus to the host cell and its subsequent entry. Newcastle disease virus (NDV) has been used as a virus vector to express different proteins successfully. The unique characters of NDV lying in its broad host spectrum and ease in production using embryonated chicken egg make it a choice of vector for expressing foreign gene. In the present work, we are reporting the characterization of the ribonuclease (RNase) activity of recombinant NDV expressing En of CSFV. The RNase activity of viral expressed recombinant Ems was found to be stable at a optimum temperature of 50 degrees C. The study will be useful to express and characterize an enzymatic protein in its native form using the NDV as a vector.