A simplified version of a mathematical model developed by Molz and Remson (1970) is used to compute “effective root distribution” for sorghum. Data from an experiment by Gardner (1964) are utilized in the computation, and the computed root distribution is compared with the measured distribution. The effective distribution is computed for 1, 3, 5, and 7 days after the beginning of the experiment, and results indicate that it is a complex quantity which varies in both space and time. Initially, the two distributions bear little resemblance, but as the soil dries due to transpiration, they become quite similar. The computations lend support to the model of Molz and Remson (1970) and might be interpreted as indicating the existence of significant impedence to moisture flow in the plant roots under moist conditions. Longitudinal variations in root surface permeability and root growth could also contribute to the computed behavior.