Evaporation rates of zinc from crystalline alpha -Ag-Zn solid solutions with various initial concentrations were measured using new evaporation equipment. The results, along with concentration profile data and SEM micrographs of the bulk material, confirmed the assumption of porous surface layers in the specimens with initial concentrations in the range 24.3-30.1 at.% Zn. Transport coefficients (including not only volume diffusion but also vapour transport in the pores) were calculated from the evaporation losses. Fairly good agreement was found between the theory of diffusion and the experiment for the alloys with concentration less than 18.3 at.% Zn. Corresponding values of diffusion coefficients were calculated from concentration profiles and evaporation losses.