This study demonstrates the possibility of enhancing the antibacterial activity and dyeing properties of cotton, polyester and their blended fabrics in one step. These fabrics were treated first with carboxymethyl chitosan (10 g/kg) to impart it antibacterial activity and enhance dye ability at the same time followed by dyeing with acid dyes and disperse dye. Results show an improvement in antibacterial activity and dye ability. It was further noted that, in all cases, the treated fabrics were more susceptible towards Gram positive bacteria (S. aureus) than Gram negative bacteria (E. coli) due to bacteria structure. The treated samples exhibited very sufficient antibacterial activity even after 25 washing cycles through durability test. Modes of interactions were proposed, and surface modification was also confirmed by FT-IR, TGA and SEM analysis.