The affects of iron on the structure, physical, and optical properties of several iron phosphate and sodium-iron phosphate glasses were investigated using x-ray photoelectron spectroscopy (XPS), Mossbauer spectroscopy, and infrared spectroscopy (IR). Archimedes method, differential scanning colorimeter and Able refractometer measurements were used to determine the glass density (d), transition temperature (Tg), and refractive index (n), respectively. XPS and Mossbauer spectra showed the presence of iron in both the Fe2+ and Fe3+(4- and 6-coordinated) states. With the increase of Fe2O3 content in the iron phosphate glasses and the increase of Na2O content in the sodium-iron phosphate glasses, the Fe2+/Fe ratio decreases and the Fe3+(4-coordinated)/Fe ratio increases. The infrared measurements showed that the increase in the Fe2O3 content or the Na2O content caused a change in coordination from FeO6 to FeO4. Finally, the relationship between the properties and the Fe2+Fe3+(4-coordination) ratio is discussed briefly.