Dimensionless Henry's law constants (air/water partition coefficient K-aw) of four volatile organic compounds (VOCs), namely, methyl tert-butyl ether, vinyl acetate, dimethyl carbonate, and diethyl carbonate, are reported. Applying headspace solid-phase microextraction (HS-SPME) in combination with gas chromatographic analysis, whose response was calibrated by the use of standard gas mixtures, K-aw values (0.001 < K-aw < 0.1) were determined in the temperature range of (10 to 45)degrees C. Replicated measurements showed a good repeatability (average relative standard deviation 2.5%, n = 144). The results were checked through additional K-aw measurements carried out using the inert gas stripping (IGS) technique at 25 degrees C, receiving intermethod deviations < 5%. Furthermore, approximate values of hydration enthalpies Delta H-hyd and hydration entropies AS(hyd) for the four VOCs were derived from linear van't Hoff fits of the K-aw(T) data, demonstrating an enthalpy-driven partition process.