The viscosities, densities, and refractive indices at 20, 25, 30, and 35 °C were determined for the systems: methyl isobutyl ketone–n-butanol (MIK–B1), methyl isobutyl ketone–sec-butanol (MIK–B2), and methyl isobutyl ketone–isobutanol (MIK–B3). From the experimental results the excess volume, excess viscosity, and excess molar free energy of activation of flow were calculated. The deviations from ideality for the excess thermodynamic function are more important for the system (MIK–B2) than for the systems (MIK–B3) and (MIK–B1). This fact is explained by the existence of hydrogen bonds in the alcohols, stronger in the primary alcohols than in sec-butanol.