Scaled multiphase versions of the Brooks-Corey and van Genuchten retention functions were used to describe saturation-capillary pressure curves measured in air-water, air-organic liquid and organic liquid-water systems in a sandy porous medium for four organic liquids during monotonic wetting phase drainage. Scaling was achieved by a linear transformation of capillary pressures using scaling coefficients which are shown to be closely predicted by ratios of measured interfacial tensions, providing that the latter are measured on fluids having contacted the porous media system. The multiphase version for the van Genuchten function described the experimental data with slightly greater precision than the Brooks-Corey function for all four organic liquid systems. A technique is introduced to ensure that when two-phase saturation-capillary pressure measurements are used to predict fluid behavior in three-phase systems, the estimated parameters imply an invariate pore geometry pertinent to the description of a rigid porous medium. (Copyright (c) 1987 Elsevier Science Publishers B.V.)