Gene therapy is the most recent face of modern biotechnology, which has shown promise of disease diagnosis and management at a newer and the most sophisticated level. The reason of enormous interest in gene therapy lies in the fact that most of lethal pathologies including hepatitis B and C, AIDS and carcinogenesis are refractory to contemporary treatments. These techniques, at least in controlled environment, allow turning on and off various genomic sequences. Relevant to this subject, RNA interference (RNAi) is the most recent, highly precise method to silence almost any gene of choice. Currently, RNAi for various disorders is being tried in humans; if this therapeutic strategy works at clinical level as well, it would be possible to design therapies against certain intractable pathologies including hepatitis C and AIDS.