A solvatochromic method was used to characterize the water sorption behavior of polymer films. Four different dyes were dissolved in various solid polymers and the relative water vapor pressure in the atmosphere was changed. Evaluated solvatochromic parameters depended not only on the amount of sorbed water but also on the kind of polymer. A linear correlation between the E(T)(30) value and Taft’s multiparameter was confirmed in both the dried and the water sorbed polymers. The correlation equation was almost identical to that obtained by other researchers in liquid solvents. These results suggest that the dissolved dyes behave as indicators of microenvironmental changes in the solid polymer film.