Viscosities and densities of {x(1) di-n-butyl ether + x(2) 1-propanol + (1 - x(1) - x(2)) n-octane} and their corresponding binary mixtures were measured at the temperatures of 293.15, 298.15, 303.15 and 308.15 K under atmospheric pressure. Kinematic viscosities were determined using a capillary viscosimeter, and densities were measured by a vibrating tube densimeter. The viscosity deviations and Gibbs free energies of activation for flow were evaluated. All the experimental values were compared with the results obtained with different predictive methods.