Isobaric vapor-liquid equilibrium (VLE) data for methanol and acetonitrile system was measured at 101.3 kPa by using equilibrium still. The results show that methanol and acetonitrile system can form a minimum temperature azeotrope. Thermodynamic consistency of the experimental data was confirmed by means of Herington semi-empirical method. The experimental values obtained were correlated by using the Margules, Van Laar, Wilson and NRTL activity-coefficient models, respectively. The binary interaction parameters of the activity-coefficient models were determined. The average absolute deviation in boiling point and vapor-phase composition were determined by comparing the experimental values with those calculated by the activity-coefficient models. The calculated maximum average absolute deviations were 0.25 K and 0.0056 for the boiling point and vapor-phase composition, respectively. Therefore, it was shown that the four activity-coefficient models used satisfactorily correlate the experimental results of methanol and acetonitrile system. (C) 2012 Elsevier B.V. All rights reserved.