Effects of the structure of polymer and nanosilica additive on the sorption and electric properties of various alginate fibers has been investigated. It has been found that regardless of the differences in the chemical structure and the presence of nanosilica, the examined types of alginate fibers show similar values of moisture absorption at relative humidity up to 85%. An exception is the fiber from sodium alginate. It has been found that the electric conductivity and the accompanying polarization processes of various types of alginate fibers depend on the chemical structure of the fiber-forming polymer. It has been found that the amount of moisture absorbed by the fiber-forming polymer of alginate fibers exerts a strong influence on their electric properties. (c) 2006 Wiley Periodicals, Inc.