The effect of replacing Fe2O3 for Na2O on the chemical durability of sodium lead silicate glasses of the compositions, (25 - x) Na2O-x Fe2O3-25PbO-50SiO(2), where x = 0,5, 10 and 15 (mol%) has been studied. FTIR, density and thermal expansion coefficient have also been measured. Replacing Fe2O3 for Na2O increases the chemical durability of the glasses. An increase in the packing of the structure is observed with increasing the Fe2O3 content as revealed by the increase in density, transition and softening temperatures and decrease of thermal expansion coefficient. These results are attributed to decreasing of the non-bridging oxygens in the glass structure as confirmed by FTIR spectra and by the decrease or vanishing of the infrared absorption peaks due to H-O-H group or water molecules vibrations. (C) 2012 Elsevier B.V. All rights reserved.