RNA interference is a powerful and rapid technique to knockout the gene expression by introducing either short interfering RNA or double stranded RNA fragments into targeted host. These RNA fragments degraded specific homologous mRNA. RNAi technology used as an essential tool in several model organisms such as invertebrates, mouse and fly to explore the role of individual gene. In recent era, RNAi is directly used in therapy of various infectious and non-infectious diseases. Variety of human diseases like cancer, viral and neuromuscular has been controlled through RNAi. Some vectors and inducible systems are available now to treat numerous disorders. This review paper provides the basis for further development of RNAi technology as a drug therapy against various human disorders.