X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy have been used to study the structure of xPbF2⋅(45 – x)CdF2⋅55B2O3 (0 ≤ x ≤ 45 mol%) glasses. XRD patterns indicated that there are no crystalline phases in these glasses. On contrary, SEM of 25PbF2⋅20CdF2⋅55B2O3 glass revealed separation of PbF2-rich phase and limited concentration of CdF2 crystallites. It is assumed that Pb2+ and Cd2+ ions have mutual ability to activate phase separation of phases related to each other. IR spectra have been analyzed to follow the change in concentration of structural species. It is assumed that both CdF2 and PbF2 partially modify the borate network, forming tetrahedral borate units and the rest forms CdF2 and PbF2 amorphous matrices. Calculated density and molar volume obtained by using the structural information agree well with the experimental data. It has been found that the volumes of structural units in the studied glasses are the same in CdF2–B2O3 and PbF2–B2O3 glasses.