Background and Aim: Chitosan-based nanomaterials have attracted significant attention in the biomedical field because of their unique biodegradable, biocompatible, non-toxic, and antimicrobial nature. Chitosan, either alone or mixed with other polymers (active agents and metallic nano composites) has been extensively used in many biomedical applications. In dentistry, chitosan acts as an anti- plaque agent and can interfere with all microorganisms, while exhibiting antibacterial activity. And therefore, is used in mouthwash, toothpaste, dental material and drugs.Hence, this study was undertaken to know efficacy of Chitosan Nanoparticles against Chitosan in oral health of immunocompromised. Methodology: In this study, swabs were taken from immune-compromised patient and were cultured for Streptococcus Salivarius, Streptococcus Mitis and Streptococcus Sanguinis bacteria. Then, the zone of inhibition was measured for Chitosan and Nano-Chitosan using Hi-Media Antibiotic Zone Scale. Result: Both Chitosan and Nano-Chitosan created inhibition zones on each bacterium. And the zones obtained were almost same with no significant difference. Statistical analysis: Results were analysed using STUDENT-T TEST and ONE-WAY ANOVA TEST. Conclusion: Chitosan and Nano-Chitosan have proved antibacterial action against Streptococcus Salivarius,Streptococcus Mitis and Streptococcus Sanguinis.