Chitosan, a polymer of glucosamine, is industrially produced by chemical deacetylation of chitin separted from shellfish. The chitosan is a polycationic polymer, therefore antimicrobial activity is one of the most important characteristics of this polymer. Poly(ethylene terephthalate) (PET) is widely used for barriers, fibers, sheets, packaging and films because of its excellent characteristics such as traarency and outstanding processability. It is light in weight, and has good impact resistance. It is one of the candidate matrice since it is inexpensive, inert, nontoxic, and readily available. The aim of this work was to evaluate the anti-bacterial and mechanical properties of chitosan based solvent-cast blends with synthetic PET. The use of packaging or coating films containing antimicrobial agents could be more efficient by sustainable release of the anti-bactericidal agents from the carrier film structure to the food surface, maintaining a high concentration. For the PET/Chitosan blend, the amount of chitosan loading was varied from 1% to 9% (W/W). Chitosan and PET were homogeneously dissolved in a ternary solvent system with different mass ratios in a triflouro acetic acid, chloroform, and acetic acid solution and processed into uniform films. Molecular interactions between chitosan and PET were investigated using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy. Morphologies of these blend films were followed using SEM. Tensile strength (TS) and elongation percent at break (%E) of the films were determined using a Universal Testing Machine (Zwick1446-60). The antibacterial activity of the samples was evaluated utilizing the colony forming unit method against three typical human pathogenic microorganisms, Escherichia coli, Klebsiella pneumonia , and Staphylococcus aureus . The results indicated that the PET/chitosan films showed a significantly higher growth inhibition rate compared with the PET film. Chitosan release from a wide range of blends was studied using the Ninhydrin method. The reaction of chitosan with ninhydrin was rapid, sensitive, and reproducible, but non-stoichiometric. Since the results obtained using the ninhydrin assay would differ for different types of chitosan, the presented data involved construction of a calibration curve and evaluation of the performance of the ninhydrin assay with the particular chitosan used in the blends. The results indicated that the PET/Chitosan blends presented significant antimicrobial property, which increased with increase in the chitosan content of the films. The release tests revealed that dissolution of the biocide glucosamine groups, i.e. the chitosan water soluble fractions, also increased with increase in the amount of chitosan content. Results obtained from ATR-FTIR spectra suggested that there exist pronounced interactions that probably resulted from hydrogen bond formation between different components. SEM images showed that the compatibility of the two polymers was reduced when the fraction of chitosan was increased. Tensile strength and elongation at break of the blends decreased with the increase in chitosan content. With the increase in chitosan content from 1 to 9%, the tensile strength tends to decrease from 50.0 to 26.6 MPa and elongation at break decreases from 78.5% to 21.1%. These results indicated that the blends became brittle with increasing the chitosan content. Keywords: Chitosan, Poly (ethylene terephthalate), Antibacterial, mechanical properties, release