Viscosities of the ternary mixture (1-butanol + n-hexane + 1-butylamine) and the binary mixtures (1-butanol + n-hexane), (1-butanol + 1-butylamine) and (n-hexane + 1-butylamine) have been measured at 298.15 and 313.15 K. Viscosity deviations for the binary and ternary systems were fitted to Redlich-Kister’s and Cibulka’s equations, respectively. The "viscosity-thermodynamic" model (UNIMOD) has been used to correlate experimental data for the binary mixtures and to predict the viscosities for the ternary system. The Group-Contribution Thermodynamic-Viscosity model (GC-UNIMOD), and the group contribution method proposed by Wu have been used to predict the viscosity of the binary and ternary systems.