The synthesis of polylactide (PLA)-b-polyethylene glycol (PEG) linear block copolymers and their use in blends with pure-PLA is described. PLA-b-PEG linear block copolymers were obtained by the reaction between poly(ethylene glycol) bis (2-aminopropyl ether) (molecular weight 2000 Dalton) with PLA in the presence of stannous octoate via trans esterification. Molecular weight measurements of the block copolymers indicated that AB and ABA type block copolymers were obtained by controlling the feed ratio in the trans esterification reactions. The copolymers obtained were purified by the fractional precipitation and then characterized by H-1-NMR, FTIR, GPC and DSC techniques. Blends of pure PLA with PLA-b-PEG displayed improved mechanical properties compared to pure PLA. Thermal, mechanical and morphological characterization of the blends were also conducted.