We studied three sodium phosphate glasses (1 − x)NaPO3 + Fe2O3 (x = 0.05, 0.1, 0.15) prepared in air in the same conditions using 57Fe Mössbauer spectroscopy in order to investigate the effect of a growing Fe2O3 addition on the features of iron sites. High spin ferric and ferrous iron in octahedral coordination is present in all the samples. We found that the distortion, compared to a regular octahedron, of the ferric and ferrous iron sites increases from the low to the high iron content samples.