Data have been assembled on gas to water partition coefficients for 374 compounds at 310K. It is shown that an Abraham solvation equation with five descriptors can be used to correlate 350 such values, as logK W (310), with R 2 =0.994 and S.D.=0.154log units. Division into a training set and a test set shows that there is no bias in predictions and that predictive capability of the equation is 0.16log units. Use of indicator variables allows the inclusion of polyaromatic hydrocarbons and polychlorobiphenyls, and for a total data set of 374 compounds R 2 =0.993 and S.D.=0.163log units. For partition from the gas phase into physiological saline (0.9% sodium chloride) at 310K, a similar equation with five descriptors correlates values for 257 compounds with R 2 =0.989 and S.D.=0.180log units. For 135 overlapping compounds for which both logK W (310) and logK W (saline) are known, the average error is only 0.032log unit, suggesting that the two data sets can be combined. For the total of 631 data points, an equation with five descriptors plus indicator variables for polyaromatic hydrocarbons and polychlorobiphenyls has R 2 =0.992 and S.D.=0.177log units.