An attempt was made to prepare antibacterial cotton fabrics that is suitable for dressing material. Chitosan wsa irradiated with γ-ray at an exposure rate of 1.85 kGy/h in the presence of air to a total dose of 40-200 kGy. Chitosan was dissolved in 0.5% acetic acid aqueous solution. Cotton fabrics were soaked in chitosan solution with different concentration, and then 1 M sodium hydroxide aqueous solution. They were dried in clean hood after being washed with distilled water. The effects of the Irradiation of chitosan, chitosan concentration, soaking time of the cotton fabrics in chitosan solution on the antibacterial properties of fabric were examined. Antibacterial effects of γ-irradiated chitosan-treated cotton fabrics were evaluated by a viable cell counting method against E. coli, S. aureus, and P. putida, respectively. Cotton fabrics treated with irradiated chitosan were found to have better antibacterial activity than those treated with non-irradiated chitosan.