Densities and viscosities of binary and ternary solvent systems which are composed of I-propanol, 1,2-dichloroethane, and benzaldehyde have been measured in the temperature range (288.15 to 313.15) K and the over entire composition range and Under atmospheric pressure From experimental data, values of viscosity deviations, delta eta, have been determined. The Calculated binary data have been fitted to the Redlich-Kister equation to determine the appropriate coefficients. Also, the experimental results are used to determine the appropriate coefficients or the Cibulka, Singh, and Nagata equations. The results provide a test of the Grunberg and Nissan equation for correlating the dynamic viscosities of binary and ternary mixtures to mole fractions