An automated total pressure measurement apparatus was used to measure PTz data that was regressed into PTxy data using the method of Barker (1953). The isothermal vapour-liquid equilibrium measurements were carried out for the five binary systems 2-methylpropane + methanol, +ethanol, +2-propanol, +2-butanol and +2-methyl-2-propanol at 313.15 K. Error analysis of the measured results is presented. Measurements were compared with predictions given by UNIFAC and COSMO-RS. All systems exhibited positive deviation from Raoult's law and azeotropic behaviour was found for the systems 2-methylpropane + methanol and 2-methylpropane + ethanol. (c) 2005 Elsevier B.V All rights reserved.