Measurements of partition coefficients between tricaprylin (glyceryl tri-n-octanoate) and water are reported for seven chlorobenzenes (1,2-dichlorabenzene, 1,4-dichlorobenzene, 1,3,5-trichlorobenzene, 1,2,3,4-tetrachlorobenzene, 1,2,3,5-tetrachlorobenzene, pentachlorobenzene, and hexachlorobenzene) between 5 degrees C and 45 degrees C. The values are compared with reported data on octanol-water and triolein-water partition coefficients. The van＇t Hoff plots of log K-OW versus T-1 exhibit linearity with values of K-OW increasing by 5%-8% over this temperature range, and the enthalpy of phase change varies from 9.7 to 16 kJ/mol. Several reasons are suggested why tricaprylin-water partition coefficients may be preferable to octanol-water and triolein-water partition coefficients when quantifying a substance＇s hydrophobicity. The mutual solubilities of tricaprylin and water are less than that of octanol and water. Tricaprylin is less volatile than octanol and, being a triglyceride, is structurally more similar to lipids. Tricaprylin is easier to purify than triolein and, because of its lower molecular mass, is easier to analyze by gas chromatography.