Dimensionless Henry's law constants k(H) (air-water partition coefficients) for a series of aromatic aldehydes and ketones were measured by using an internal standard method. It was demonstrated that the technique works well for both liquid and solid species. The k(H) values of these compounds, which usually are difficult to be determined experimentally, are in the order of 10(-6) to 10(-3). The measurements were carried out under atmospheric pressure and at various temperatures [(273 to 298) K]. The temperature dependence of k(H) was also studied, and the van't Hoff parameters were calculated. All the data are reported with the corresponding standard deviations and uncertainties at the 95% confidence level. The theoretical dipole moments in the gas phase were computed by utilizing Cerius(2) molecular modeling software to justify the discrepancies among the k(H) values of the isomers. These calculations exhibit linear relationships between the dipole moment and k(H) within each isomer series.