Poly(vinyl alcohol) (PVA) films modified with Magnesium chloride hexahydrate (MgCl2 center dot 6H2O) were prepared by casting method. The prepared films were characterized by X-ray diffraction measurements (XRD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and mechanical testing. It was found that the presence of MgCl2 center dot 6H2O had considerable effects on the crystallinity, thermal, and mechanical properties of PVA films. The crystallization of PVA film was interrupted and the degree of crystallinity of PVA film decreased with the addition of MgCl2 center dot 6H2O. The glass transition temperature of PVA film decreased with the addition of MgCl2 center dot 6H2O. After modifying with MgCl2 center dot 6H2O, PVA film became soft, with lower tensile strength and higher elongation at break. The presence of MgCl2 center dot 6H2O could significantly increase the moisture content of PVA films and this may be the cause of the plasticizing. POLYM. ENG. SCI., 2012. (C) 2012 Society of Plastics Engineers