The interfacial tension (I.F.T.) of petroleum reservoir fluids are commonly predicted by either the parachor method or the scaling law. Both methods have been evaluated against literature data of binary systems. The predictive capability of the methods have been improved by a simple modification of the original correlations. The superiority of modified methods have been demonstrated by comparing predicted results with experimental I.F.T. values for two gas condensate fluids at wide ranges of pressure and temperature.