60P2O5-40Fe2O3 glass was synthesized and 57Fe Mössbauer spectroscopy study was presented. The main goal of the research was to investigate structural changes of local environment of iron ions during gradual crystallization of the glass. It was observed that some changes were evidenced at temperature of heat treatment higher than 400°C, above which content of tetrahedrally coordinated Fe3+ was increased in cost of octahedral sites. This led to formation of areas of nucleation of α-FePO4. Crystallization of α-Fe3(P2O7)2 and Fe2P2O7 was also observed.