The optical properties of new glasses in the ZnO-CdO-SiO2system containing high CdO levels (50-90 wt. %) has been determined. The refractive-index variation versus CdO and ZnO composition has been considered. Likewise, the refractive index and spectral transmittance in the 20 0-2600-nm range for these glasses has been carried out. From these optical measurements it can be stated that glasses in the ZnO-CdO-SiO2system would be adequate for infrared windows or as laser matrices.