The diffusion of various inert and of hydrogen-bonding solutes into aliphatic alcohols was considered. The diffusivities of benzene, p-dichlorobenzene, biphenyl, and triphenyl methane in methanol, ethanol, n-propanol, n-butanol, n-pentanol, and n-heptanol were measured at 25°C. for low solute concentrations. An equation was developed for the limiting values of the binary mutual diffusion coefficient in complex-forming mixtures. This equation, used in conjunction with the Wilke-Chang correlation, gave a considerable improvement over existing predictive methods for the diffusivity of inert solutes, mono- and polyhydroxy alcohols, and water in aliphatic alcohols.