Nowadays LLDPE waste is contributing seriously to the environmental problems, and hence modification ofLLDPE to promote biodegradation is desirable. Several data indicated that to be biodegradable, the polymer chain must contain chemical bonds susceptible to enzymatic hydrolysis or oxidation initiating the biodegradation process This research aimed to modifY LLDPE through copolymerization, to create hydrolysable and oxidizable functional groups along the LLDPE main chain. To create this function, copolymerization LLDPE with maleic anhydride without initiator in laboplastomill had been done. Copolymerization has been done at ISOaC with 60 rpm rotation. Analysis of functional groups and physical properties ofLLDPE before and after modification have been done by IR, UV, XRD, tensile strength and % elongation at break. FTIR and UV analysis indicated the occurrence of double bond, non-cyclic anhydride and keto acid at LLDPE main chain. Tensile strength 28%, melt indeks indeks 99%, elongation at break 203% and the degree of crystallinity increase 163% compare to the original LLDPE. It could be expected that this copolymerization might be one of an alternative way to modifY a synthetic polymer for possible biodegradation. Key words: LLDPE, Anhidrida maleat, Laboplastomi. Hasnah Muin Jurusan Teknik Kimia, Fakultas Teknologi Industri Universitas Islam Indonesia Yogyakarta