Abstract: Electron transfer processes between sensitizing dyes and AgBr grains were studied by ESR technique. Neither sensitizing dyes nor AgBr grians under exposure to light gave ESR signal. The AgBr grains absorbing dyes gave no signal in the dark. The ESR signals were observed for the dyes whose highest occupied levels were 0.7 eV higher than the top of the valence band of AgBr. Paramagnetic centre was formed by the positive hole of dyes (Dye^©). The stronger the dye shows its ESR signal the more it desensitizes AgBr crystals.