Isothermal vapor-liquid equilibrium data for 2-methyl-1-butanol + 3-methyl-1-butanol were measured using a static synthetic method at temperatures of 343.15, 353.69, 368.15, and 404.45 K. Additionally, excess enthalpy (H-E) data for the system were measured with an isothermal flow calorimeter at 363.13 K. The experimental data were correlated using temperature dependent interaction parameters for the NRTL model which were fitted to all measured data. The system was chosen as a test system for distillation columns.