Lead borate glasses of the type x PbO - (100-x) B2O3 with 20 mol% < x < 70 mol% were investigated by IR reflectance spectroscopy in the mid and far infrared region. The mid infrared spectra supply information about the content of structural borate groups in dependence of the PbO concentration. The far infrared spectra show a band of the Pb++ cation vibrations within the borate glass network between 100 and 190 cm−1. This band shifts towards higher frequencies with the rise of the PbO content of the glass.