Solutions of various problems related to soil contamination by nonaqueous phase liquids (NAPL) require a knowledge of capillary pressure-saturation relationships. In soil-water-air systems, this relationship is frequently denoted as the soil water retention curve. Results of measurements of capillary pressure-saturation relationships for two two-phase systems (air-water and air-oil) in two soils (loamy sand and silt loam) are presented. A prediction technique based on a modification of Leverett's concept was applied. The suitability of the method was tested for loamy sand and silt loam by comparison of the scaling factors based on theoretical interfacial tension values with the actual scaling factors between two capillary pressure functions. The data measured shows that the scaling factors for soil-air-water and soil-air-oil consist of the ratios of the interfacial tensions and the wetting angles of both liquids. Both parameters cannot easily be predicted and should be studied in detail.