Abstract <p>The influence of the content of structure-forming components of sodium aluminum iron phosphate glass on its phase composition, structure, and resistance to leaching at elevated temperatures as necessary characteristics of vitrified iron-containing high-level waste during its deep disposal was studied. It was found that the samples studied (mol %), 40.0Na₂O–12.5Al₂O₃–12.5Fe₂O₃–35.0P₂O₅, 35.0Na₂O–12.5Al₂O₃–12.5Fe₂O₃–40.0P₂O₅, and 35.0Na₂O–10.0Al₂O₃–10.0Fe₂O₃–45.0P₂O₅, consist of a single amorphous glass phase and have high hydrothermal stability. The leach rate of sodium and phosphorus from the above samples under semidynamic (on the 28th day) and dynamic (on the 10th day) conditions at 90 and 95°C, respectively, was about 10⁻⁵ g (cm² day), that of aluminum, within the range (2–10) × 10⁻⁶ and (0.6–2) × 10⁻⁵ g/(cm² day), respectively, and that of iron, within the range (7–12) × 10⁻⁷ and (0.4–3) × 10⁻⁶ g/(cm² day), respectively.</p>