Chitosan has been widely used as biomaterials due to versatile properties. However, the inherent brittle properties are still hard to control. To overcome these, PEG has been used for flexible mechanical properties. Although the incorporation of PEG into chitosan has been developed, studies on various parameters of PEG have not been conducted. In this study, we prepared injectable chitosan/PEG hybrid hydrogels using enzyme mediated cross-linking. Physicochemical properties of hydrogel were investigated by varying the parameters of PEG (e.g. content, M.W., geometry). The hydrogels were fully characterized and cyto-compatible. It was found that the various parameters of PEG in hybrid hydrogels could control their physicochemical characteristics. In conclusion, chitosan/PEG hybrid hydrogels with tunable physicochemical properties are expected to be a promising biomaterial for various applications. Acknowledgement: [MOTIE/KEIT] 10062079, 2019R1A6A1A11051471