Diffusivity measurements between two inorganic solids, zinc oxide and zinc aluminate, in the absence of reaction was undertaken with particle size, compaction pressure, diffusion temperature and diffusion time as variables. The present work was mainly concerned with the experimental techniques of measurement and the establishment of the concentration profile for diffusion of zinc oxide into the zinc aluminate through which fundamental as well as concentration and temperature diffusivities were determined. Activation energies required for fundamental as well as concentration and temperature diffusion were calculated and reported. Generalized correlations were also established. © 1985, The Society of Chemical Engineers, Japan. All rights reserved.