In recent years magnetic resonance imaging has become a very efficient tool for in vivo quantification of water content and water behavior in living tissues. We have applied this technique to the study of the in vivo hydration profile in heel skin layers by quantification of the mobile water proton density versus depth. Effects of a bath, a moisturizer and repeated soaping are present. Hydration profiles by magnetic resonance imaging delineate two different structures in stratum corneum: an outer layer where hydration can be modified by external mechanisms and an inner layer where hydration is not altered. The main interest of this method lies in the fact that the physical signal is exactly located, as spatial encoding is the basis of in vivo imaging. This method differs from other noninvasive methods which acquire an averaged signal from a nondelimited volume of interest.