The results of investigation of phosphorescence of benzaldehyde in porous matrix are presented. As matrix was used porous glass obtained by sol-gel technology. Spectra of phosphorescence and its decay kinetics have been obtained for solvent-containing samples. The influence of the matrix on the above-mentioned parameters of phosphorescence has been revealed. It is shown that the character of this influence is determined by the interaction of the activator molecules with matrix walls and depends on the nature of used solvent.