Poly(lactic acid) (PLA)/poly(ethylene glycol) (PEG) blends containing reactive ethyl cellosolve-blocked polyisocyanate (EC-bp) as a crosslinking agent with the goal of making sustainable eco-friendly materials were prepared using solvent casting method. Effects of such crosslinking agent and PEG additive on the properties of the prepared blends were investigated and compared. The morphology of the blends, evaluated by environmental scanning electron microscopy (ESEM), indicated that improved interfacial adhesion between PLA and PEG were achieved by the crosslinking effect of EC-bp. Tensile properties and water resistance were also studied and the results showed that these properties of EC-bp modified blends were significantly enhanced in comparison with the unmodified ones. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) results showed that the degree of crystallinity (?c) of the blends was enhanced in the presence of PEG domains, whereas crystallization rate was decreased by addition of EC-bp. Dynamical mechanical analysis (DMA) showed that enhanced storage modulus and heat resistance of the blends were obtained when EC-bp was introduced as a crosslinking agent. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012