Diffusion of water in hydrated starch, hydrated starch plus sucrose, and diffusion of glucose, potassium, magnesium and ascorbic acid in potato tissue, i.e. a major natural source of starch, were analyzed with Eyring's diffusion theory and the compensation relations. The results implied that there may be an isokinetic temperature for the diffusion of water in amioca (amylopectin, one of the major macromolecular components of starch) and hylon 7 (native corn starch). Having an isokinetic temperature may imply that diffusional jump occurs via formation of similar activated complexes. Although the compensation relations were satisfied, there was no isokinetic temperature with diffusion of water in hylon 7 plus sucrose and diffusion of glucose, potassium, magnesium and ascorbic acid in potato tissue, therefore the compensation relations with these two systems were considered only as empirical correlations for estimating the diffusivities.