Currently, a popular era in nanomedicine is the implementation of RNA nanoparticles for various diseases and their diagnosis. RNA interference (RNAi) involves the arrangement of gene mediating mechanisms where coding and non-coding are carried out. The targeted control of gene utterance via siRNA system by nanocarriers showed an epic impact on modifying therapeutic efficacy. The article endeavours to highlight the mechanism of siRNA with concern to possible applications which are established on cancer therapy. In the current scenario to discuss the possible anti-viral effectiveness of nanoparticles with particular reference to SARS-CoV. Self-assembled nanoparticle (NP) is developed and it competently delivers to small interfering RNA (siRNA) intravenously to the tumour. The nanoparticle was found by mixing with siRNA, carrier, DNA, and lipids, preceded by after-change. Newly FDA appreciation of the first polymer-drug and additional ones in the clinically linked RNA polymer has to be highly therapeutic and diagnostic value. It has been established to be a particularly useful means for cell-type definite delivery of other RNA therapeutics like siRNA. While RNAi has helped speed up the discovery and understanding functions of a gene, it also has great potential as a therapeutic and potentially prophylactic modality. This article stated the development in the RNA polymer and also provides some examples of their diagnostic applications and therapeutics special emphasis on the anti-cancer and antiviral strategy. Patisiran and Givosiran are the recently approved si-RNA based products available in the market.Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.