Aqueous solubility relationships of aromatic and aliphatic solutes differ from one another in two important regards: (a) Solubilities of aliphatic solutes do and those of aromatic solutes do not show important dependences on solute dipolarity/polarizability (as measured by the solvatochromic parameter, π*), and (b) dependences on the solute hydrogen bond acceptor basicity parameter, β, are about one-fourth smaller for aromatic than for aliphatic solutes. Solubilities of 70 liquid and solid aromatic solutes containing up to three fused rings are well correlated by the equation: log Sw = 0.57 - 5.58VI/100 + 3.85β - 0.0110(mp - 25); r = 0.9917, sd = 0.216. VI is the computer calculated intrinsic (van der Waals) molar volume. Liquid aliphatic solutes follow a rather different relationship: log Sw = 0.05 - 5.85VI/199 + 1.09π* + 5.23β n = 115, r = 0.9944, sd = 0.153. The differences between aliphatic and aromatic solutes may be due, in part, to "vertical stacking" in aromatic liquids.