Using a semiempirical quantum chemical method (AM1), various properties (dipole moment, charge distribution, geometrical parameters, etc.) of 331 compounds were calculated. Various linear functions of these properties and their combinations were fitted to reproduce experimental aqueous solubilities. An 18-parameter function was derived that is reasonably simple, yet appears to be able to describe the aqueous solubilities of a wide range of organic compounds. The parameter set is essentially the one used in a recent similar study of octanol-water partition coefficients. The derived equation has important predictive value.