The impact of thermo-hydric behavior of underwears were studied on comfort. The Pearson method is used to make a correlation between physical and thermo-hydric properties of fabrics. Three parts have been studied, i.e. (i) thermal properties, (ii) hydric properties, and (iii) coupling between thermal and hydric properties. It has been observed that thermal properties are affected by porosity, moisture regain and fabric density; hydric properties are influenced by fabric weight, thickness, air permeability and density. The last parameter, related on the coupling effect, depends on fabric weight, porosity, moisture regain, air permeability and density. The sorption properties of the various textile fabrics in variable wet environment have been studied with dynamic vapor sorption apparatus (DVS). From the fitting of the sorption isotherm curves with the Park’s model, it was established the kind of fibers are the main factors influencing each component of this one.