Abstract Thermo- and photodoping of glassy As 2S 3, As 2Se 3 and As 50Se 50 films with Zn is investigated. Existence of photo- and thermoinduced diffusion of Zn into chalcogenide films is clearly shown. Zn-dissolution and Zn-diffusion processes were studied separately. A large difference was demonstrated for the photoinduced processes in structures fabricated by evaporation of Zn under and over the chalcogenide film. The processes at the photodoped – non-doped interface were shown to determine the rate of the whole photodoping effect. Some peculiarities of the lateral Zn-photodiffusion are demonstrated. Structure and some properties of the Zn-photodoped films are studied.