A method for the evaluation of the interfacial polarity profiles is introduced based on a previously proposed model (ref 10). This numerical procedure depends on the knowledge of a few, reasonably well-known bulk solvent properties-such as the static and high-frequency dielectric constant. Water correlation decay length is argued to affect the results of the data analysis only little as long as its value is sufficiently smaller than the effective width of the interfacial region. The corresponding analysis of the hydration force data for the phospholipid bilayers shows that the interfacial polarity profile for such systems can be approximated well by a simple exponential function. The latter is uniquely defined in the region covered by the experimental data. However, without additional assumptions no extrapolations in the experimentally unexplored region are possible. In order to learn more about the molecular mechanism and the range of the surface hydration, as well as about the hydration-induced changes in the interfacial structure, more and more detailed experimental hydration force data should be collected.