The excess molar volume V-E, the viscosity deviation Deltaeta and the excess Gibbs energy of activation Delta(G)*(E) of viscous flow are calculated from density and viscosity measurements of six mixtures of 1-propanol, 1-butanol, 1-pentanol, 1-heptanol, 1-octanol and 1-decanol with tri-n-butylamine over the entire range of mole fractions at 303.15 and 313.15 K. The values of V-E of all six systems are very large and negative. Except for 1-propanol+tri-n-butylamine, the magnitude of negative deviations in viscosity increases with chain length of alkanol. The results have been explained considering mixed associated species of type A(i)B involving alkanol (A) with tri-n-butylamine (B) through O-H . . . N bonds. The viscosity data have been correlated with the equations of Grunberg and Nissan, Tamura and Kurata, Hind, McLaughlin and Ubbelohde, Katti and Chaudbri, McAllister, Heric, and of Auslaender.