Viscosities of the ternary mixture (2-butanol + n-hexane + 1-butylamine) and of the binary mixtures (2-butanol + n-hexane) at 298.15 and 313.15 K, and (2-butanol + 1-butylamine) at 313.15 K have been measured at atmospheric pressure. Viscosity deviations and excess Gibbs energy of activation of viscous flow for the binary and ternary systems were fitted to Redlich-Kister's and Cibulka's equations, respectively. To correlate experimental data of ternary system from binary ones, different empirical and semiempirical equations have been used (Nissan and Grunberg, Hind, Frenkel, McAllister, Katti and Chaudhri, Heric and Iulan) and their parameters have been calculated. The "viscosity-thermodynamic'' model (UNIMOD) has been applied to correlate experimental data for the binary mixtures and to predict the viscosity for the ternary system. The Group Contribution-Thermodynamic Viscosity model (GC-UNIMOD), and the group contribution method proposed by Wu have been employed to predict the viscosity for the binary and ternary systems.