Numerical study has been performed to analyse evaporation of a single droplet composed of a binary mixture of ethanol and iso-octane. The Navier-Stokes equations are solved in conjunction with VOF multiphase model to track the liquid/gas interface over time. Ethanol and iso-octane form a highly non-ideal mixture and therefore the UNIFAC group contribution method was used to determine the vapour-liquid equilibrium (VIE). Source terms due to interfacial mass transfer were implemented in the continuity, momentum, energy and species equations. Commercial computational fluid dynamics solver, Ansys Fluent 13.0 was used in this study. VLE, mixture transport properties and source terms due to interfacial mass transfer were implemented using user defined functions. Parametric study to analyse the effect of free stream temperature and composition, droplet temperature and composition was performed.