Abstract: Vapour liquid equilibrium data are the basic need in the design of distillation columns. In the present study, VLE prediction of four binary azeotropic systems namely ethanol-water, acetone-water, ethanol-benzene and methanol-water was carried out using UNIQUAC and UNIFAC Models. UNIQUAC parameters of the chosen systems were computed using Newton Raphson’s technique. Computations of UNIFAC Model were done using ASOG method. VLE predicted from these models was validated using experimentations carried out in othmer VLE still and thermodynamic consistency test using Redlich Keister method. It was observed that both models are able to fit the experimental VLE data for all the systems. The results show that all the four systems are minimum boiling azeotropes having positive deviation from ideality.