MicroRNA (abbreviated miRNA) is a small single-stranded non-coding RNA molecule which contains 22 nucleotides found in plants, animals and some viruses, which can has important regulatory roles in RNA silencing and post-transcriptional regulation of gene expression. As we know viruses attack plants many times because they are exposed to open environment. Rice tungro disease is one of the destructive diseases of rice which causes on average 2% losses in rice production in India. MiRNA plays a vital role in plant defense against viruses. In this book, computational approaches have been proposed to explore the possibility of endogenous rice plant miRNAs having role in antiviral defence by targeting the mRNA of di erent genes of rice plant infecting tungro viruses of both Rice Tungro Spherical Virus (RTSV) and Rice Tungro Baciliform Virus (RTBV).