A method is proposed by which the partial molal entropies of aqueous complex ions can be correlated in a simple manner as a function of the ratio of their charge to interatomic distance. The agreement obtained between the observed values and those calculated by this method has been shown to be within the accuracy of the experimental data. It is also demonstrated that when the complexing agent is water alone (i.e., no complexing) the proposed equation reduces to an expression similar to that previously obtained by Powell and Latimer for simple monatomic ions.