PbO-P2O5+ xMnO2 (02 on structural and optical properties of glasses have been investigated using different characterization techniques. The effect of both glass composition and MnO2 content on the generation of radiation-induced defects has been investigated. The intensity and the position of the induced bands are found to depend on the type and composition of glass, concentration of the dopant and also on the irradiation dose. Experimental results indicate that the undoped glass reveals before irradiation strong and broad ultraviolet absorption which is related to the co-sharing of absorption due to both trace iron impurities and lead ions (Pb2+). The band gap energy is found to decrease with the increasing content of MnO2 in the glasses, while different irradiation doses showed remarkable effect on the band gap which decreases to semi conducting range. The effect of gamma irradiation also takes place, the band gap decreases from 4.15 to 2.9 eV and from 3.84 to 2.8 for indirect transition for both G1 and G4 respectively also for all glass systems.