The aim of the present review was to study about the CRISPR Cas system and there role in genome editing, bacterial virulence and antibiotics resistance. CRISPR Cas system is an integral part of prokaryotic (Bacteria and Archaea) immune system that provides protection against viral infection. When bacteria recognize viral DNA inside it, bacteria incorporate small fragment of viral DNA into its genome at specific site termed as CRISPR locus. Insertion of viral DNA at CRISPR locus allows to remember, diagnose and clear the viral infection by the mechanism of sequence specific Adaptive Immunity. CRISPR Cas system is sustainable to combate with the mutation developed in viral genome that help viruses to escape from bacterial CRISPR Cas based immune system. CRISPR Cas system is a molecular mechanism of prokaryotic microorganism. It acts as bacterial natural adaptive immune system against phages, plasmids and foreign genomic elements. Mostly prokaryotes uses their CRIPR Cas system to enhance the integrity of their cell membrane that inhibit the permeability of antimicrobials from host body into the bacterial cells. CRISPR Cas system also help bacteria to evade from the host immune system by suppressing the activity of their immune receptors e.g. TLR. CRISPR Cas system also help bacteria to attach with the host body and replicate with in host body. It can develop antibiotic resistance in pathogenic bacteria, enhance their pathogenicity and can survival in host body.Novelty Statement | CRISPR Cas system is an integral part of prokaryotic immune system that provides protection against viral infection and involved in genome editing, bacterial virulence and antibiotics resistance.