The rapid growth of nanotechnology has introduced the use nanoparticles in water disinfection processes as an innovative approach with low or no toxicity to the consumers and environment. From these, chitosan nanoparticles (CNs) have been received growing interest as chitosan is a naturally occurring polysaccharide with well-known antimicrobial properties against bacteria, viruses and fungi. In this context, we propose that CNs might be used as antimicrobial agent for drinking water disinfection. Consequently, the objective of this study was to demonstrate the effective antimicrobial activity of CNs on the survival of faecal indicator Escherichia coli.