Poly (lactic acid) (PLA) is attractive as a substitute for classical polymers due to its biodegradability and sufficient mechanical properties. In the present work, various blend ratios of poly (lactic acid) (PLA) and triallyl cyanurate (TAC) were prepared by melt compounding in an Xplore microcompounder and molded by Xplore model microinjection molding device. TAC was used as a coagent. After compounding process, PLA/TAC composites were exposed to a gamma irridation at various adsorbed doses ranging from 0 to 100 kGy. The mechanical properties of PLA and PLA-TAC were performed by tensile testing. The chemical structure of PLA and TAC was visualized by Fourier Transform Infrared (FTIR) spectroscopy. The thermal properties of the composites were investigated by Differential Scanning Calorimetry (DSC). Results showed that neat PLA was strongly degraded by gamma irradiation while PLA-TAC composites are less affected because gamma irradiation promoted the TAC layer distribution within the PLA matrix. The elongation at break of composites decreased with the increasing TAC content. However, E-modulus has improved about 15% compared to pure PLA. DSC results indicated that a sharp decrease in degree of crystallinity (Xc%) of PLA/TAC composites was obtained for higher gamma irridation doses. FTIR analysis showed that gamma irradiation of PLA lead to oxidation reactions of ester groups inducing the formation of hydroxyl groups which can be present in hydroperoxides or alcohols. Keywords: PLA, crosslinking, gamma irridation