Poly (vinyl alcohol), PVA for short, films doped with different concentrations of cesium chloride(CsCl) (0% , 2% , 4% , 6% , 8% , 10% , 12% , 14% ,16% ) were prepared by solution casting method to study the effect of this salt on thermal properties of PVA by using thermogravimetric analysis (TGA) .It was found that the dopedPVA films with concentrations(14% and 16%) of CsCl aremore thermal stable than PVA while doped PVAfilms with concentrations ( 4% and 6%) of CsCl are less thermal stable than PVA and the dopedPVA films with concentration of ( 2% , 8% , 10% and 12%) are almost as thermal stable as PVA. Fourier transform infrared spectroscopy (FTIR) was also used to investigate complexation between CsCl and PVA and was foundthat the doped PVA films with concentration (2% , 4% , 6% and 8%) of CsClshowno significant shifts in wave numbers of the characteristic bands of PVA while doped PVA films with concentrations (10%, 12% ,14% and 16% ) of CsClshow a significant shifts to a higher values in wave number of stretching vibration of (-OH) comparing to PVA indicating well complexation between CsCl and PVA.