Composite "phosphor-in-glass" based on high refractive index lead-silicate glass and YAG:Ce powder has been developed and synthesized. Glass composition optimization in the order to reduce scattering at glass/phosphor interfaces has been performed. Samples of composite light-converting materials for white LEDs were prepared by sintering glass powders and phosphor at 600 °С. Spectral, luminescent and structural properties of the obtained composites have been investigated. White LEDs based on the composite glass phosphor materials obtained have been tested. The color temperature of the probe LED was found to be 4370 K with the luminous efficacy 58 lm/W.