Diffusion data at 950àare estimated as function of concentration in the multicomponent ߭NiAl phase grown in a nickel-base superalloy by the pack-aluminizing technique. The calculated interdiffusion coefficients are observed to be concentration dependent within the examined composition range. Interdiffusion coefficient of Al and Ni in the multicomponent ߭NiAl phase is obviously less than the reported data. It is speculated that variation in the thermodynamic properties and the structural factor due to the solid solution of the alloying elements may be responsible principally for the decrease in interdiffusion coefficient of Al and Ni in the multicomponent ߭NiAl phase.