This International Standard specifies a laboratory method for simultaneous determination of the unsaturated hydraulic conductivity and the soil water retention characteristic. This standard is applicable only to measurement of the drying or desorption curve. Application of the method is restricted to soil samples which are, as far as possible, homogeneous. The method is not applicable to soils which shrink in the range of h(m) = -0 cm to h(m) = -800 cm. The range of determination of the conductivity depends on the soil type.