Quantitative structure-property relationships (QSPRs) have been examined for the aqueous solubility of halogenated benzenes, polychlorobiphenyls, polybromobiphenyls, and polychloronaphthalenes at 20 to 25°C. Multiple regression correlations of aqueous mole fraction solubility (X) with molecular size descriptors (molecular weight, total molecular surface area, or various zero-order molecular connectivity indices) and a combined molecular symmetry and structure descriptor (R* Molecular size descriptor) are reported. A generalized correlation takes the form ofwhere 1 ≤ m ≤ 2,airefers to theith regression coefficient, andRis a molecular redundancy index. The best correlation found, from the standpoint of reduced standard deviations and calculational simplicity, does not contain a melting temperature term (a2= 0). Derived QSPRs enable estimation of aqueous solubilities based solely on structural information.