The literature on the physicochemical properties of liquid binary mixtures shows that most such systems exhibit nonlinear behavior. As a result, rigorous data and equations capable of affording a reliable estimate of the behavior of such mixtures are needed. The present study offers an equation of correlation providing a reliable estimation of the properties (density, viscosity, surface tension and refractive index) of binary mixtures of liquids as a function of mole fraction. In order to assess the validity of the proposed equation, the latter has been applied to reference binary mixtures, and comparisons have been made of the experimental values of the studied magnitudes versus those obtained with the mentioned equation, the polynomial equation of Redlich-Kister. the equations of Heric and Mc Allister, the polynomial of the third degree and the Gladstone-Dale equation. (C) 2009 Elsevier B.V. All rights reserved.