In a recent publication, Suresh and Koga suggested that the molecular electrostatic potential minimum (V-min) could be used as a quantitative measure of the "sigma donating power" of substituted phosphorus(III) ligands. In support of this assertion, they showed linear correlations between a number of physicochemical properties and V-min. Our examination of the analyses of the sets of experimental data used to support this assertion shows unequivocally that the variations in the properties cannot be described by a single parameter. Therefore, the utility of V-min as a measure of the "sigma donating power" of substituted phosphorus(III) ligands remains unsubstantiated.