(Liquid liquid) equilibrium data for type I ternary and quaternary systems of representative compounds of gasoline and methanol as the oxygenate compound were measured at T=293.15 K and atmospheric pressure. The experimental data were correlated with the NRTL and UNIQUAC models. The numerical procedure to calculate the (liquid liquid) equilibria of the systems studied is based on the minimization of the system Gibbs energy along with thermodynamic stability tests, to find the most stable state of the system. Good agreement was found between experimental equilibrium data and those calculated with both thermodynamic models for all the ternary and quaternary systems studied. (C) 2013 Elsevier B.V. All rights reserved.